Organometal halide perovskite (OMHP) is a promising material for the light-weight and high-efficiency solar cells. In fact, perovskite solar cells (PSCs) using OMHP have demonstrated remarkable advancements, where the power conversion efficiencies (PCEs) are exceeding 26%. In this lecture, current situation and future prospects of the high performance perovskite solar cells and modules are summarized. The composition of OMHP is recognised as one of the key factors in the improvement of the stability and efficiency. Many groups investigated mixed cation and mixed halogen perovskite absorber toward the high efficiency. For the improvement of the stability, K+-doped OMHP is good for keeping relatively high performance. The crystal lattice structure of the organometal halide perovskite is also important for both absorption and photophysics of them, whereas the micro-structural aspects within the simple organometal halide perovskite are still controversial issue. In our study, direct observation of the microstructure of the thin film organometal halide perovskite using transmission electron microscopy was investigated. In the case of “n-i-p” structural PSCs, FAPbI3 nanoparticles (NPs) were used for the making process of the FAPbI3 layer. The NPs improves the crystallinity, uniformity, and morphology of the bulk FAPbI3 perovskite films. The improved FAPbI3 layer lead to a reduction in charge recombination and a boost in charge transfer efficiency, enabling the optimized PSCs to achieve a remarkable peak power conversion efficiency (PCE) of 25.68 % with improved stability. In the case of “p-i-n” structural PSCs using defectless SAM, PCE reach to 25.93 % at the optimized condition.

The exponential growth of Internet of Things (IoT) devices presents a critical challenge in sustainable energy provision. High-efficiency ambient photovoltaics integrated with artificial intelligence offer a promising solution for self-powered, smart IoT systems. Dye-sensitized solar cells (DSCs) optimized for indoor light harvesting have been developed using novel copper coordination complexes as redox mediators. These mediators regenerate dyes with an overpotential of only 0.1 eV. By employing co-sensitization strategies with dyes such as XY1 and L1, power conversion efficiencies of up to 38% have been achieved under 1000 lux fluorescent light, with open-circuit voltages exceeding 1.0 V.(1) A key innovation is the ”zombie” solar cell concept, where copper complexes form a solid-state hole transport material upon electrolyte evaporation. These devices maintain high efficiency and stability after drying, due to the formation of an amorphous Cu(II/I)(tmby)2 hole transport layer. Raman spectroscopy and impedance analysis have revealed the unique charge transport mechanisms in these systems. Further advancements have been made with the development of dynamic dimer copper coordination redox shuttles. These complexes transition between Cu(I) dimers and Cu(II) monomers during the redox process, enabling a two-electron transfer mechanism that enhances charge transport while minimizing recombination. In addition to traditional molecular complexes, one-dimensional copper coordination polymers have been introduced as hole transport materials. These materials exhibit band-like charge transport with modeled effective hole masses as low as 6me, providing a sustainable alternative to heavily doped organic semiconductors.

These material advancements have been translated into practical devices, integrating DSCs with microcontrollers to create self-powered IoT nodes. On-device machine learning, including convolutional neural networks for image recognition tasks, has been implemented. Long short-term memory (LSTM) networks manage energy use dynamically, adapting computational loads to available light, thus ensuring optimal performance in varying ambient conditions.

This interdisciplinary approach, which spans from molecular design to device engineering and artificial intelligence, demonstrates the critical synergy between materials chemistry and advanced computing in addressing global energy challenges. These findings not only advance ambient photovoltaics but also open new avenues for sustainable, intelligent technologies capable of operating autonomously in low-light environments.

Organic-inorganic halide perovskites have emerged as promising materials for next-generation optoelectronic devices due to their exceptional photophysical properties. Among them, α-formamidinium lead tri-iodide (α-FAPbI₃) with a cubic symmetry (space group of .) has garnered attention as a potential absorber in solar cells for its narrow bandgap and superior stability. However, the fundamental mechanisms underlying its high performance remain elusive. As recent studies reported incorporation of methylammonium chloride (MACl) to stabilize α-FAPbI3, herein, we propose that crystallization process of α-FAPbI3 can be kinetically controlled by adjusting MACl concentration. We examined higher concentration of MACl induces slower crystallization kinetics, resulting in larger grain size and [100] preferred orientation. In this presentation, centro-symmetry breaking in [001] preferred oriented α-FAPbI₃ thin films (POF) arises from inevitable anisotropic strain during film formation will be discussed. Using circular polarization-dependent pump-probe transient absorption (CPTA), we observe Rashba-type band splitting exclusively in POF, indicating symmetry breaking. Angle dependent X-ray diffraction and photoluminescence (PL) reveal significant residual stress in POF compared to randomly oriented films (ROF), confirming strain-induced lattice distortion. Furthermore, time-resolved PL (TRPL), and time-resolved microwave conductivity (TRMC) measurements reveal top-back inhomogeneous carrier dynamics and anisotropic charged carrier mobility, supporting the presence of strain-induced symmetry breaking. Furthermore, we present an amorphous TiO2 and V2O5-x passivation layers, deposited by atomic layer deposition (ALD) at low temperature (< 50 ℃), on Spiro-OMeTAD to prevent metal-induced interfacial degradation while maintaining the overall performance. Finally, we have fabricated perovskite solar cells (FTO/SnO2-based ALD-ETL/FAPbI3/2Dperovskite/Spiro-OMeTAD/Au) and confirmed increased PCE (23.91 %) measured under AM 1.5 G. Not only PCE, but also device stability with ALD-TiO2 and V2O5-x layers was dramatically improved. It was confirmed through ion contents profiling using ToF-SIMS that the improvement of the stability in PSC adopting ALD-TiO2 and V2O5-x comes from preventing the metal ion diffusion. In conclusion, we have demonstrated high PCE and stability of PSCs.  

This study elucidates the role of phenolphthalein (PHTH) as an additive in enhancing the photovoltaic performance and operational stability of formamidinium lead iodide (FAPbI₃) perovskite solar cells (PSCs) fabricated under ambient conditions. Incorporation of PHTH into the perovskite precursor solution markedly improved the film quality and device performance. At an optimal concentration of 10 mg mL⁻¹, the power conversion efficiency (PCE) increased from 14.6 % to 19.9 %, accompanied by negligible hysteresis. Furthermore, the PHTH-modified PSCs retained approximately 90 % of their initial efficiency after 720 h of storage in air (25 ^oC, 30 % relative humidity), whereas the control devices degraded to ~30 % under identical conditions (Figure 1). The superior performance is attributed to the dual functionality of PHTH: it acts as a molecular adhesive promoting the formation of highly ordered FAPbI₃ crystals, and as an O-donor Lewis base that coordinates with Pb²⁺ and FA⁺ ions. These interactions suppress non-radiative recombination and facilitate the phase transformation from the non-perovskite δ-phase to the photoactive a-phase. This work demonstrates that PHTH is an effective molecular additive for achieving high-efficiency, air-stable FAPbI₃-based PSCs[1].

Perovskite solar cells (PSCs) have emerged as one of the most promising next-generation photovoltaic technologies, owing to their high power conversion efficiency (PCE) and relatively simple fabrication processes. Laboratory-scale devices have already surpassed 27% efficiency, and large-area modules have approached PCE of 20%, attracting broad interest from both academia and industry. Now, numerous companies are actively exploring commercialization pathways. Nevertheless, long-term operational stability and cost control remain the primary barriers to large-scale deployment. In this presentation, I will introduce the progress in the commercialization of PSCs with a particular focus on module manufacturing costs and levelized cost of electricity[1]. A comparison with crystalline silicon solar cells is presented to evaluate the economic potential of PSCs. Based on this analysis, key research and development are proposed from a cost perspective. Furthermore, I will introduce our researcher works on promoting the efficiency and stability of PSCs from aspects of crystallization, passivation, and ion-migration blocking. Especially, we constructed a composite electrode of copper-nickel (Cu-Ni) alloy stabilized by in situ grown bifacial graphene[2]. The device with the copper-nickel electrode showed an efficiency over  24% (1cm²) and stability: 95% of their initial efficiency is retained after 5,000 hours at maximum power point tracking under continuous 1 sun illumination.

Perovskite solar cells (PSCs) have rapidly emerged as one of the most promising photovoltaic technologies, with power conversion efficiencies exceeding 27%. However, their poor long-term durability remains a major obstacle to commercialization. The intrinsic instability of perovskite materials and their interfaces—particularly under exposure to moisture, oxygen, heat, and light—leads to rapid degradation of device performance. In this study, we demonstrate significant improvement in the operational stability of PSCs through a comprehensive materials and interface engineering approach. Novel organic defect-passivation materials were synthesized to effectively neutralize ionic defects and suppress non-radiative recombination at the perovskite surface. In addition, new hole-transport materials with high thermal stability and stable energy levels were developed to minimize interfacial diffusion and enhance hole extraction. Interface engineering between the perovskite and transport layers was further optimized by introducing molecularly compatible interlayers that reduce energy level mismatch and prevent ion migration. Moreover, the perovskite absorber layer composition and crystallization dynamics were precisely tuned to achieve dense, uniform films with reduced trap densities. Structural modification of oxide-based electron transport layers provided additional protection against moisture ingress and improved interfacial contact. As a result, the optimized devices exhibited excellent environmental and thermal stability, maintaining over 90% of their initial efficiency after prolonged operation under continuous illumination and elevated temperature. This work provides an effective strategy for achieving both high efficiency and long-term stability in PSCs, offering practical insights for their future commercialization.

Metal-halide perovskites (MHP) are highly promising optoelectronic materials due to their exceptional properties and versatile fabrication methods. These materials are crucial for solar cells and optoelectronic devices, as well as quantum emitters.^1-2

Thermal evaporation has emerged as a pivotal approach to achieve precise control over film thickness, composition, and interfacial quality, enabling stress-free deposition, surface modification, and scalable device fabrication—key parameters for advancing perovskite optoelectronics.

In this talk, I will present how we have addressed the challenges of scalability and reproducibility in perovskite solar cell (PSC) fabrication—both critical for sustainable large-scale deployment. We demonstrate that a sixfold increase in deposition speed can be achieved while preserving film quality and power conversion efficiency. This accelerated co-evaporation route enables cost-effective, annealing-free PSC production, greatly simplifying the manufacturing workflow.³

Building on the capability of thermal evaporation to deliver films with nanometer-level thickness control and high uniformity, we have extended this approach to design perovskite-based Multiple Quantum Wells (MQWs).⁴ These engineered heterostructures allow tuning of carrier confinement, excitonic coupling, and quantum interference phenomena—unlocking new functionalities in light emission, carrier dynamics, and quantum optoelectronic device architectures. MQWs thus represent a transformative platform for tailoring the electronic band structure and achieving unconventional photonic and quantum responses beyond conventional bulk perovskites.⁵

Overall, these advances not only overcome major barriers to scalable PSC production but also open new frontiers in quantum-confined perovskite optoelectronics, underscoring the versatility and technological potential of thermally evaporated perovskite materials for next-generation energy and photonic applications.

References:

1) Min, H., et al., Nature, 2021. 598, 444.; Yoo, J.J., et al., Nature, 2021. 590 587.

2) J. Li et al., Joule 2020, 4, 1035; H.A. Dewi et al., Adv. Funct. Mater. 2021, 11, 2100557; J. Li et al., Adv. Funct. Mater. 2021, 11, 2103252;

3) Dewi et al. ACS Energy Lett. 2024, 9, 4319−4322; Dewi et al, ACS Energy Materials 2025

4) Advanced Materials 2021, 33, 2005166; L. White et al. ACS Energy Lett. 2024, 9, 83;

5) L. White, ACS Energy Lett. 2024, 9, 4450. L. White, ACS Energy Lett. 2024, 9, 4450.

For meeting the future electricity demands of a Net-Zero 2050 society, particularly at the terawatt scale, solar technologies that combine high power conversion efficiency with low cost per peak watt are indispensable. Before the emergence of perovskite solar cells (PSCs), only a few material systems could simultaneously satisfy these requirements. This presentation traces the evolution leading to practical solid-state PSCs. It begins with early photovoltaic concepts and the use of inorganic quantum dots such as nanocrystalline PbS as light harvesters—materials that, despite their promise, suffered from severe surface-defect-mediated recombination. Recognizing these limitations, methylammonium lead triiodide (MAPbI₃) perovskite was introduced as an alternative light absorber. However, its initial use in liquid-electrolyte dye-sensitized architectures yielded poor efficiencies (3–4% in 2009) and instability due to perovskite dissolution. A major breakthrough came in 2012 with the demonstration of a 9.7% efficient and 500-hour-stable PSC employing a solid-state hole-transporting layer [1], establishing PSCs as a viable photovoltaic technology. Subsequent rapid advancements pushed efficiencies to nearly 27% using FAPbI₃ absorbers, surpassing many existing technologies. Current research now centers on further enhancing efficiency and operational durability to enable industrial deployment. Achieving commercially viable PSCs will require intensified efforts in additive and interface engineering, together with a deeper mechanistic understanding of degradation pathways.

Perovskite solar cells (PSCs) have emerged as promising candidates for next-generation ultra-light photovoltaic technologies due to their bendable perovskite layers, enabling film-type solar cells.[1] Their fabrication through solution-based coating and printing of electron/hole transport layers and organic-metal-halide perovskites offers the potential for low-cost production. PSCs have achieved power conversion efficiencies exceeding 20% in small-area devices (~1 cm²), positioning them as high-efficiency, low-cost alternatives to conventional solar cells.

To realize the commercialization of PSCs, it is essential to overcome challenges related to long-term durability under environmental stressors such as heat, moisture, and light, as well as to establish scalable manufacturing processes. At AIST, we are developing robust materials and interface technologies to mitigate degradation, alongside advanced evaluation methodologies for optimizing layer thickness and band alignment. [2-10] One critical issue is the reduced thermal stability caused by dopants in hole transport materials (HTMs). To address this, we synthesized novel dopant-free organic HTMs, achieving over 1000 hours of operational stability at 85 °C. In parallel, we explored alternative dopants such as phenyl ethyl ammonium (PEA)-TFSI, which maintained high efficiency under thermal stress. To combat moisture-induced degradation, we introduced 1,4-phenyl bisphosphonic acid (PBPA) as an additive in the perovskite layer, significantly enhancing moisture resistance.

For acceleration of material screening and device optimization, we developed a fully automated PSC fabrication system capable of full-layer coating, back electrode deposition, and laser scribing. This presentation will provide a comprehensive overview of our research and development efforts at AIST, aimed at enabling the practical deployment of perovskite solar cell technologies.

Tokyo Chemical Industry (TCI) is a global supplier of laboratory chemicals and specialty materials, and also leading the next-generation solar technology by providing high-quality and reliable materials, including metal halide perovskite precursors and materials for carrier transporting.

 Organic-Inorganic Perovskite Precursors
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Perovskite Precursor for Solar Cell Purified Lead(II) Iodide

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High Purity Perovskite Precursor Purified Lead(II) Bromide

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Perovskite Precursor Lead Acetate Anhydrous

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Perovskite Precursors Tin(II) Iodide, Tin(II) Bromide

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n-Type SAM Forming Agent Enabling Efficient Perovskite Solar Cell: PANDI (New)

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Hole Selective Self-Assembled Monolayer (SAM) Forming Agents: PACzs

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SAM Formation Reagent with Face-on Orientation to Substrate Surface: 3PATAT-C3

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SAM Formation Reagent with Three Carboxylic Acid Moieties as Anchors: 3CATAT-C3

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Hole Transport Materials For Stable and Practical Perovskite Solar Cells: TOP-HTMs

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High Quality Hole Transport Material: Spiro-OMeTAD

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Dopants for Organic Electronics Research

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Solar Cell Materials (PSC, OPV, DSSC Materials)

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In this short talk, these highly useful materials will be introduced including most recently commercialized new products.

Functional organic molecules capable of defect passivation in halide perovskite crystals work for suppressing charge recombination loss, leading to enhancement of photovoltage.¹ Amino group-bearing molecules, such as phenylethylamine (PEA) halide and amino acids, are widely applied for passivation of organic/inorganic perovskites. We modified the perovskite-hole transport layer (HTL) interface with an oriented PEABr monolayer and improved V_OC close to 1.2V for a 1.51 eV bandgap perovskite, minimizing the V_OC loss (0.3V) from the SQ limit, similar to the best performance of GaAs device. While interfacial modification using oriented functional monolayers enhance the photovoltaic performance, recombination caused by iodine defects in the bulk polycrystalline structure is a key target for improving performance. Regarding all-inorganic perovskites (CsPbX₃, X=I, Br, bandgap of 1.9 to 2.1eV), iodine defects are passivated with 2,5-thiophenedicarboxylic acid (TDCA) and the CsPbX₃ devices achieve high V_OC of 1.4 to 1.5V.² As visible-light absorbers, CsPbX₃ devices achieve power conversion efficiency (PCE) over 34% under indoor lighting.³ Recent cell designs are evolving to use self-assembled monolayers (SAMs) at the interface, and inverted devices architecture typically use SAMs at the perovskite-TCO electrode interface. Although many bifunctional molecules have been used as p-type SAMs capable of selective hole transport, relatively few devices utilize n-type SAMs. A challenge of our device design opened the door to the possibility of creating lattice-matched SAM-modified interfaces in perovskite solar cells.⁴ We started research to design a new device architecture in which interfaces of perovskite layer are fully functionalized with SAMs. Junction interfaces were modified with p-type SAM and n-type SAM that replace HTL and electron transport layer (ETL), respectively. SAM-based devices were fabricated for different perovskite compositions, and all photovoltaic devices free of charge transport layers exhibited good photovoltaic performance with perfect bifacial power generation. They demonstrated high stability against long term light soaking as an advantage of not using bulk HTL and ETL layers.⁵ This method of interface modifications will be effective for fabrication of lead-free perovskite solar cells.^6,7 It will also be applied to fabrication of plastic film type flexible modules, which is a goal of our module development project. Recent advances in the architecture of perovskite solar cells based on interfacial molecular engineering will be presented.

References

1. T. Miyasaka, editor, Perovskite Photovoltaics and Optoelectronics ―From Fundamentals to Advanced Applications―, Wiley-VCH, Weinheim, 2021, ISBN: 978-3-527-34748-3.
2. Z. Guo, S. Zhao, N. Shibayama, A. K. Jena, I. Takei, T. Miyasaka, Adv. Funct. Mater. 2022, 32, 2207554.
3. Z. Guo, A. K. Jena, and T. Miyasaka, ACS Energy Lett. 2023, 8, 90.
4. T. Wu, T. B. Raju, J. Shang, L. Wu, J. T. Song, C. A. M. Senevirathne, A. Staykov, S. Wang, S. Ida, N. Shibayama, T. Miyasaka, T. Matsushima, and Z. Guo, Adv. Mater. 2025, 37, 2414576.
5. Z. Hu, N. Saito, M. Ikegami, N. Shibayama, and T. Miyasaka, submitted.
6. N. B. C. Guerrero, M. D. Perez, N. Shibayama, and T. Miyasaka, Chem. Sci. 2025,16, 5807.
7. L. Cojocaru, A. J. Jena, M. Yamamiya, Y. Numata, M. Ikegami, and T. Miyasaka, Adv. Sci. 2024, 11, 2406998

The efficiency of perovskite-based tandem solar cells has rapidly increased, primarily driven by those with Si bottom cells, which have reached a highest certified efficiency of 34.9%. In addition to Si, thin-film bottom cells made from low-bandgap materials such as chalcogenides, perovskites, and organics, also show promise for applications where Si-tandems are not suitable, such as lightweight, flexible or space-based solar cells. Regardless of the bottom cell material, the interface between the subcells is a critical component in determining the performances of tandem solar cells. This interface must transmit both electrons and photons simultaneously, but in opposite directions (in the case of p-i-n devices). In this presentation, our recent research progress on optimizing the interface between subcells in highly-efficient perovskite-based tandem solar cells with various bottom cells such as Si, CZTSSe, and CIGS will be introduced.[1-5]

Halide perovskites have emerged as transformative materials across optoelectronics, primarily driven by their success in the photovoltaic field. Their exceptional properties, including a direct, tunable bandgap and low non-radiative recombination, are not only ideal for solar energy conversion but are also foundational for creating high-performance light-emitting diodes (LEDs) and advanced photocatalytic systems. However, the dual challenges of lead toxicity and long-term instability have hindered their widespread adoption. While lead-free tin (Sn) halide perovskites are the most promising alternative, their poor stability, particularly the rapid oxidation of Sn2+ has severely limited the performance and lifetime of all device architectures.

In this presentation, we demonstrate a significant leap forward in stabilizing Sn-based perovskites. We detail how a synergistic approach combining targeted additive engineering and controlled light soaking passivates critical defects, enhancing the material's intrinsic stability. This strategy leads to a remarkable improvement in the operational lifetime of our solar cells, and we dissect the underlying mechanisms that go beyond simply preventing oxidation, enhancing stability and photoconversion performance.

Crucially, these advancements have profound implications for other Sn-perovskite applications. Considering Sn-perovskite LEDs, we show how additives and the use of proper injecting contacts can enhance LED performance. Furthermore, we will explore the application of these stabilized materials in photocatalysis, especially the use of 2D tin perovskite powders for HI splitting and H2 production in aqueous media, highlight the material recycling possibilities. This work presents a unified strategy to overcome the core stability issues of Sn-perovskites, unlocking their potential not only for next-generation photovoltaics but also for efficient lighting and solar-driven chemistry.

Hybrid tin–lead (Sn–Pb) perovskite solar cells hold strong potential for single-junction and tandem applications owing to their tunable bandgap and extended near-infrared absorption. However, their performance remains limited by interfacial recombination, uncontrolled crystallization, and inefficient charge transport. In this work, we propose an integrated strategy that concurrently addresses these challenges through interfacial engineering, hole transport layer optimization, and crystallization control. First, PEDOT:PSS is dedoped with sodium hydroxide, which effectively lowers its carrier concentration and mitigates interfacial recombination losses [1]. Texturing PEDOT:PSS enhances light scattering and minimizes optical reflection, further improving photocurrent generation [2]. Second, tailored PTAA derivatives are introduced as hole transport layers to fine-tune energy level alignment and promote efficient hole extraction[3]. Finally, chaotropic additives such as GaSCN are utilized to regulate nucleation kinetics, yielding uniform, defect-suppressed films in narrow-bandgap, lead-lean perovskites [4]. As a result, the optimized devices achieve open-circuit voltages exceeding 0.9 V, short-circuit current densities above 32 mA cm^-2, and power conversion efficiencies over 22%, together with improved operational stability. Mechanistic insights from in situ photoluminescence, transient optoelectronic, and morphological analyses reveal how the combination of interface and growth control enhances charge extraction and suppresses nonradiative recombination.

In recent years, three-dimensional lead-free halide perovskites (HPs) have attracted increasing attention, largely due to advances in stabilizing these compounds against oxidation. The substitution of lead—an element with well-known toxicity—via both homovalent (Sn, Ge) [1,2] and heterovalent (+1/+3 metal pair) strategies, [3] along with the reduction of dimensionality from 3D to mixed 3D/2D and fully 2D frameworks, has yielded materials with promising photovoltaic performance. Notably, the enhanced hydrophobic nature of low-dimensional HPs has enabled power conversion efficiencies (PCEs) approaching record values, [4] while also addressing the environmental and stability limitations of archetypal Pb-based bulk HPs. 
Building on recent experimental insights, this work first examines from first-principles pristine Pb-based 2D and mixed 2D/3D HPs, emphasizing their distinct electronic and optical features and providing a comparative analysis with their Pb-free counterparts. [5] Special attention is paid to the critical influence of excitonic effects in quantum-confined systems and the fundamental relationship between symmetry and exciton behavior. [6]
Focusing on lead-free variants, the study also explores the protective function of native oxide layers developing on mixed (Sn, Ge)-based 3D HPs.[7] Remarkably, a dual nature is identified depending on whether the surface oxide adopts a crystalline or amorphous structure.

Tin–lead (Sn–Pb) perovskites have emerged as highly promising materials for near-infrared (NIR) perovskite photodetectors (PPDs) due to their broad light absorption and superior NIR responsivity.[1] However, the heavily doped hole transport layer (HTL), PEDOT:PSS, often causes severe interfacial recombination, thus limiting device performance.[2] To overcome this challenge, we introduce a simple yet efficient dedoping strategy utilizing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to modulate the electronic properties of PEDOT:PSS and enhance overall device efficiency.[3],[4] Comprehensive analyses, including UV–Vis–NIR spectroscopy, Raman characterization, electrical testing, and surface potential mapping, are conducted to systematically optimize the dedoping effect. The DBU treatment effectively passivates interfacial traps, suppresses nonradiative recombination, and promotes improved perovskite crystallinity. As a result, the dedoped PEDOT:PSS-based photodetectors exhibit remarkably reduced dark current, outstanding detectivity up to 10¹⁴ Jones in the 380–960 nm range, and a broad linear dynamic range (LDR) of 84.5 dB. This facile dedoping strategy not only boosts device performance but also offers a practical pathway for developing high-efficiency NIR perovskite photodetectors.

The performance and stability of perovskite solar cells are susceptible to the quality of the charge transport layer, particularly when self-assembled monolayers (SAMs) are used as hole transport layer. It has been reported that SAM molecules tend to aggregate into colloidal because of concentrations and solvent effects. However, the underlying mechanism behind this remains unclear. In this study, we regulated the pH of SAM solutions via water-containing and water-free methods to elucidate the effect of pH on SAM colloidal aggregation and associated film quality. We then designed and synthesized a novel material, 6-aminohexylphosphonic acid hydrochloride (6AHPACl), to be added to the (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid) Me-4PACz solution. Apart from the anticipated colloid aggregation suppressing for better film coverage, this co-SAM strategy served multiple functions that could not be achieved by pH modulation alone. They include better anchoring of the 6AHPACl to the underlying NiOX layer via covalent bonding; improved energetics for the SAM/perovskite interface due to the dipole moment offered by the 6AHPA+; and better wettability and therefore better quality of the overlaying perovskite layer. Compared to conventional Me-4PACz approach, this co-SAM strategy enabled a champion efficiency of 22.8% to be achieved by a wide-bandgap (1.67 eV) perovskite solar cell with a high open-circuit voltage (VOC) of 1.25 V and a fill factor of 84.9%. When applied to a 1cm2 monolithic perovskite-silicon double junction, the champion device produced a certified efficiency of 29.1% and a high VOC of 1.95V. Outstanding stabilities were also achieved by encapsulated devices. One retained 95% of its efficiency after 1010 Thermal Cycles (-40℃ to 85℃), more than five times the number required by the International Electrotechnical Commission (IEC) 61215 standard. Another encapsulated double junction device successfully passed the IEC 61215 Humidity Freeze test by an additional 16 Humidity Freeze cycles for the first time to date, marking a significant milestone in the reliability of perovskite-silicon double junction solar cells. These findings will guide future designs of SAM for efficient and durable perovskite single junction and multi-junction photovoltaics. 

The degradation of perovskite solar cells is a complex process governed by the dynamic interplay between electronic and ionic phenomena. These coupled processes give rise to characteristic slow responses, hysteresis, and memory effects that strongly influence device performance and stability. In this work, we employ a dynamic model that integrates both charge transport and ionic migration to analyze these effects in detail. The model successfully reproduces key experimental observations, including capacitive and inductive features in the impedance spectra. In particular, the occurrence of an inductive loop can be interpreted as a chemical inductor, originating from the delayed feedback between ionic redistribution and electronic recombination or transport processes.

Such behavior is closely related to the strong hysteresis and memory effects previously observed in perovskite memristors, where the combination of electronic and ionic mechanisms leads to non-linear and history-dependent responses. By combining impedance spectroscopy and time-domain transient measurements, we identify distinct time constants associated with charge accumulation, ion migration, and recombination, and we track their evolution during degradation. The analysis reveals two predominant degradation pathways: (i) reduced charge collection, resulting in lower photocurrent, and (ii) enhanced recombination, leading to a loss in photovoltage.

By correlating these mechanisms with their dynamical electrical signatures, we establish a comprehensive physical framework that connects hysteresis, chemical inductance, and degradation phenomena in perovskite solar cells. This approach provides a powerful diagnostic route to understand and mitigate performance losses in emerging perovskite optoelectronic devices.

Poly(triarylamine) (PTAA) has become the standard hole transport layer (HTL) of choice for fabricating stable NIP perovskite solar cells, due to its superior thermal and environmental stability. However, the efficiency of these PTAA based devices typically lags their 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene (Spiro-OMeTAD) counterparts. Addressing this performance shortfall typically requires complex post treatments, that may limit device scale up.

Here we utilise a rationally designed Trityl salt to instantly and efficiently p-dope PTAA directly in solution phase, facilitating high conductivity films. In our preliminary results we demonstrate devices that achieve high device performances that rival those of Spiro-OMeTAD and surpass the stabilities of traditional Spiro-OMeTAD recipes.

Crucially, we note that the trityl salt doping proceeds via a previously unreported oxygen induced pathway for PTAA and several other donor polymer materials. Therefore, we present the first mechanistic investigation into this novel mechanism.

This facile solution phase doping strategy proves promising both for the advancement of stable polymer based HTLs for NIP perovskite solar cells, as well as other charge transport applications in optoelectronics and beyond.

Perovskite solar cells (PSCs) utilizing poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA) as hole-transport materials (HTMs) in n-i-p structures have promising thermal stability compared with those employing spiro-OMeTAD, which is the most widely used HTM. However, PTAA-based PSCs often exhibit lower efficiencies than spiro-OMeTAD-based ones, presumably due to the absence of perovskite passivation techniques suitably combined with PTAA HTMs. In terms of perovskite passivators, phenylalkylammonium (PRA)-based passivator is one of the most major categories as it is effective in improving PSC performances taking advantages of its large adsorption energy over perovskite surface. However, the conventional PEA-based passivation suffers from thermal stability issues. In the case of phenylethylammonium (PEA), for instance, the conventional PEA-based passivation suffers from thermal stability issues; under thermal stress even at moderate temperatures for a short duration (e.g., 50 °C for several minutes), the overlayer of the perovskite passivated with PEA iodide transforms to a two-dimensional (2D) perovskite of (PEA)₂PbI₄ (n = 1), which hampers carrier transfer, thus negating the passivation effects. ^[1]

   Herein, we propose a simple strategy to address the thermal stability issues using PRA-bis(trifluoromethylsulfonyl)imide (PRA-TFSI) additives for PTAA HTM.^{[2] [3]} During the HTM deposition with the PRA-TFSI additive over perovskite layers, the PRA cations spontaneously passivated the perovskite presumably exploiting the large adsorption energy, forming a monolayer-like passivation overlayer.^[4] The resulting PRA-based passivation did not exhibit crystallization to the detrimental 2D perovskite at 85 °C; hence, it did not cause PV performance drop due to the thermal stress. The PSCs with optimal PRA-TFSI addition resulted in effectively enhanced PV performances, achieving a 23.2% power conversion efficiency. The PV performance enhancement can be attributed to both the improved affinity at the PTAA/perovskite interface, which is crucial in combining PTAA HTMs yet hardly attainable by aliphatic-ammonium-based passivators, and the PRA passivation effects. This study provides novel insights into widely used PRA-based passivators and paves the way for perovskite passivation effectively combined with thermally stable PTAA HTMs.

Organic hole-selective layers (HSLs) play a pivotal role in achieving high-efficiency inverted perovskite solar cells (PSCs), particularly under indoor illumination. The chemical structure and molecular configuration of HSLs critically determine their hole transport capability and interfacial contact with perovskite layers. While functional groups are commonly introduced to enhance energy level alignment and film formation, the effects of their substitution positions, as well as the influence of spacer units and linker lengths, remain underexplored. Investigating these individual molecular design factors can help create more favorable interfacial environments for perovskite crystallization, suppress interfacial recombination, and ultimately enhance device efficiency and stability. Indoor photovoltaic devices based on perovskites are particularly promising due to their tunable bandgaps, high absorption coefficients, and excellent spectral match with common indoor light sources such as LEDs and fluorescent lamps. Through interfacial engineering using newly designed HSLs, inverted CsFAPbI_3-xBr_x PSCs achieved a PCE exceeding 20% under one-sun equivalent illumination and over 40% under indoor LED lighting, highlighting the potential of molecularly tailored HSLs for next-generation indoor energy-harvesting applications.

This study focuses on improving the stability and fill factor limitations of current n-i-p structured perovskite solar cells. Conventional hole-transport materials (HTMs), such as 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), often require dopants to enhance conductivity due to their intrinsically low charge mobility. However, the introduction of dopants or additives can negatively affect device performance and stability. Hydrophilic dopants may accelerate perovskite degradation through moisture penetration, while others can chemically corrode the perovskite layer or diffuse under bias or thermal stress, leading to interfacial accumulation and long-term instability. Moreover, carrier transport imbalance and interfacial recombination in n-i-p structures significantly restrict the fill factor.

To solve these issues, a series of donor-acceptor (D-A) copolymers were developed as dopant-free HTMs. A composite HTL composed of PBDT-DFQ_x-CT and MeO-2PACz was employed, and thermal treatment was used to promote the self-assembled monolayer (MeO-2PACz) to bond effectively with MoO₃, improving molecular ordering and interface quality. The resulting FA_0.97MA_0.03Pb(I_0.97Br_0.03)₃-based n-i-p perovskite solar cell achieved a power conversion efficiency  of 21.3%, with an open-circuit voltage (V_oc) of 1.07 V, short-circuit current density (J_sc) of 25.0 mA/cm², and a fill factor (FF) of 79.3%. Furthermore, the device retained over 90% of its initial efficiency after 700 hours of storage, demonstrating remarkable operational stability. This work provides new insights into the design of dopant-free HTLs for efficient and stable n-i-p perovskite solar cells.

Perovskite solar cells (PSCs) have attracted much attention due to their high-energy conversion efficiency and low production cost. However, the issue of stability is still remained. Our group focuses on the fundamental studies of PSCs, including development of materials for compact layer, active layer, and back electrode, as well as interface passivation of PSCs.

The simple process by using several small organic and inorganic molecules for interface passivation of devices. We successfully fabricated seamless interfacial contact carbon electrodes for low-cost PSCs through hot-pressing and solution passivation methods. The resulting PSCs with carbon electrodes exhibit excellent PCEs. The devices also show good stability than the conventional devices.

We also using interface engineering strategy by passivating with 4-nitrophenyl phosphate (PNNP) for [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) to improve the NiOx/perovskite (PVK) interface. This technique enhanced the surface uniformity and hydrophilic nature of the NiOx/Me-4PACz, while promoting favorable growth of PVK crystal orientation. Furthermore, the PNNP effectively mitigates the generation of defects at the NiOx surface and the underlying PVK, ultimately significantly improving the interfacial charge transfer efficiency. Consequently, efficiency of F-PSCs rose from 21.46% to 23.66%. Due to better stress distribution within the PVK and stronger adhesion at the NiOx/PVK boundary, the F-PSCs retained 80% of their original efficiency even after undergoing 10000 bending cycles.Notably, PNNP exhibited an outstanding capacity to capture PbI2, contributing to the device's potential for reducing lead leakage under operational conditions.

I will also introduce our group other interface passivation research results of perovskite solar cells.

The rise of all-printed carbon-based perovskite solar cells marks a paradigm shift toward scalable and sustainable next-generation photovoltaics. Especially when adopting a hole-transport-layer-free design, both processing steps and cost are reduced, while long-term operational stability is significantly improved. Within this context, piezoelectric drop-on-demand inkjet printing can be employed as a powerful enabler for scalability, reproducibility, sustainability and digital precise fabrication route. Building upon this foundation and advancing from proof-of-concept devices to manufacturable solar modules, this work demonstrates a fully ambient-air processed and high-throughput production route for perovskite technology. Inkjet printing is employed as the primary deposition technique for nearly all functional layers. Special attention has been paid to the development of a perovskite precursor ink, derived from centimeter-scale single crystals, formulated with low-lead composition, using industrial-grade reagents, and processed in a green solvent, with its colloidal stability exceeding three months under dark storage. Through the optimization of this perovskite precursor ink and drying dynamics, the mitigation of the coffee-ring effect is attained, resulting in a uniform, defect-free perovskite active layer, which is an essential prerequisite for high-quality photovoltaic devices. Complementarily, a new carbon paste is also proposed, engineered for efficient charge transport and back-contact layer, which is applied using blade coating for the scalable fabrication of carbon electrode, ensuring uniform film formation, while maintaining full compatibility with printing-based device assembly. Upscaling from laboratory-scale cells to module-level devices demonstrated high efficiency and cost-effectiveness, with efficiencies exceeding 12% on 1500 cm² (upscaling loses 8<%_reldec⁻¹, geometrical fill factor ≈70%), and the “bill of materials” and efficiency-adjusted specific costs to be estimated on the order of 30 €/m² and 0.5 €/W_p, respectively.

Industrial adoption of perovskite photovoltaics needs processes that are robust, antisolvent free, and compatible with large areas. We present a lead acetate based ink that replaces methylammonium with ammonium to stabilize volatile intermediates and promote uniform crystallization without using an antisolvent. The films show enlarged grains and longer photoluminescence lifetimes, and devices scale from cells to mini-modules by blade coating with durable performance during thermal holding at 65 °C. [1] Building on this ink, wide bandgap absorbers near 1.66 eV are obtained by introducing a small chloride fraction into the solution, which improves crystallinity and suppresses nonradiative recombination. These devices deliver open circuit voltages around 1.22 V and power conversion efficiencies near 19 percent while preserving the simplified process and good storage stability. [2] To further reduce interfacial losses, thiocyanate assisted recrystallization in isopropanol increases precursor solubility and drives passivator uptake, while the cation identity steers whether passivation concentrates at the top surface or the buried interface. A pairing of ammonium thiocyanate with MEO-PEAI improves carrier lifetime, lowers interface recombination, and enhances thermal and light stability, giving champion efficiencies above 24 percent. Together these results outline design rules that link ink formulation to interface control and provide a practical route to scalable, efficient, and stable perovskite solar cells. [3]

Organic photovoltaics (OPVs) have drawn considerable interest as emerging renewable energy technologies owing to their low production cost, mechanical flexibility, and compatibility with scalable fabrication methods. Although recent developments have pushed the power conversion efficiency (PCE) of OPVs beyond 20%, further improvement is essential to compete with conventional silicon-based devices. Among the factors influencing OPV performance, the optimization of interfacial layers—particularly charge transport layers—is crucial for controlling energy level alignment, facilitating selective charge extraction, and minimizing recombination losses.

In this study, a novel perylene diimide (PDI)-based interfacial material, BO-P106, was synthesized to overcome the limitations of conventional metal oxide electron transport layers (ETLs) that require high-temperature processing. BO-P106 enables the formation of smooth, pinhole-free films with excellent interfacial contact, effectively tuning energy alignment between the active layer and the electrode. Devices incorporating BO-P106 achieved PCEs of 14.60% in inverted structures and 17.73% in conventional configurations, demonstrating its superior versatility. Furthermore, when employed as a hole-blocking layer in perovskite solar cells, BO-P106 effectively suppressed hole injection and exhibited comparable performance to the benchmark material BCP.

These findings underscore the potential of BO-P106 as a multifunctional interfacial material capable of enhancing efficiency, stability, and compatibility across diverse photovoltaic systems, providing valuable insights for the future development of high-performance organic and hybrid solar cells.

Interface engineering plays a decisive role in enhancing charge extraction and reducing energy losses in wide-bandgap (WBG) perovskite solar cells, which are key to high-performance indoor photovoltaics. In this study, we design and investigate a new series of carbazole-derived self-assembled monolayers (SAMs) employing a short n-propyl (C3) alkyl linker between the carbazole core and the phosphonic acid anchoring group. Three derivatives—3C-H, 3C-OMe, and 3C-Ph—were synthesized to explore the effects of terminal substitution (hydrogen, methoxy, and phenyl) on molecular dipole moment, interfacial energetics, and photovoltaic performance. These SAMs act as independent hole-selective layers on NiOx-coated ITO substrates in inverted (p–i–n) WBG perovskite solar cells. Consequently, the optimized WBG perovskite device achieved an impressive open-circuit voltage (V_OC) of 1.23 V, short-circuit current density (J_SC) of 21.53 mA cm⁻², and a power conversion efficiency (PCE) of 21.59% under AM 1.5 G illumination. Under indoor LED light (3000 K, 1000 lux), the same device reached a record indoor efficiency of 41.77%, surpassing previously reported carbazole-based SAM-modified WBG perovskite cells.
This work provides critical insight into how subtle molecular-structure variations in carbazole-derived SAMs can tune interfacial energetics and device performance. The results establish C3-linked phenyl-carbazole SAMs as a robust, solution-processable strategy for realizing highly efficient and stable WBG perovskite indoor photovoltaics.

All-solid-state solar cells based on organometal trihalide perovskite absorbers have already achieved remarkable power conversion efficiencies (PCE) exceeding 27%. Research on perovskite solar cells is now progressing toward commercialization. However, several technical challenges must be addressed to enable their widespread adoption, including long-term stability, large-scale fabrication processes, and the mitigation of lead-related environmental concerns. Additionally, flexible perovskite solar cells utilizing plastic substrates have potential applications in niche markets, such as portable electronic chargers, electronic textiles, and large-scale industrial roofing.

This talk will present our recent efforts to develop sustainable perovskite solar cells with minimal environmental impact. Specifically, we will introduce a recycling technology for perovskite solar cells, covering the regeneration of lead-containing perovskite layers and the recycling of gold electrodes and transparent conducting oxide glass. Furthermore, we propose a closed-loop recycling process for toxic solvents used in both the fabrication and recycling of perovskite solar cells. The implementation of eco-friendly, solvent-based green processing techniques for high-efficiency, sustainable perovskite solar cells will also be demonstrated. Moreover, we will discuss recent progress in the development of flexible perovskite modules for use in unmanned high-altitude air vehicles.

Heterojunction interfaces play a critical and dominant role in charge carrier dynamics in various optoelectronic devices, including organic photovoltaics (OPVs), organic photocatalysts, and perovskite solar cells.  Here, I will discuss the critical role of these interfaces in the following three topics: 1) the charge generation in single-component organic semiconductor photovoltaics, 2) the formation of long-lived charge carriers in organic semiconductor nanoparticle in aqueous solutions, and 3) the enhancement of open-circuit voltage (V_OC) in perovskite solar cells.  In the first topic, we will discuss the charge generation in single-component OPVs by evaluating the exciton binding energy of neat films composed of extended π-conjugated molecules, such as Y6, and comparing their charge generation efficiency to blended films to identify the primary charge generation sites.  In the second topic, recent studies have shown efficient hydrogen generation by using organic semiconductor blend nanoparticles in aqueous solutions, suggesting that charge carriers would survive for a long time enough to contribute to photocatalytic reaction effectively.  We will discuss the origin of this long-lived charge carriers by comparing the charge dynamics of blend thin films measured in nitrogen versus in water.  In the third topic, we will discuss the effect of interface modification using self-assembled molecules at the interface of electron-transporting layer/perovskite within n-i-p structure tin-based perovskite solar cells, demonstrating how this interfacial engineering suppresses charge recombination and leads to a significant increase in the open-circuit voltage.

Perovskite solar cells (PSCs) have recently demonstrated outstanding power conversion efficiency (PCE) surpassing 26%. Nonetheless, the intrinsic instability of lead halide perovskites (LHPs), the light-absorbing materials in PSCs, poses a significant challenge to their commercialization. A major challenge of perovskite solar cells (PSCs) lies in their intrinsic instability under harsh environmental conditions. Although extensive efforts have been made to improve stability through various additives, such approaches have typically provided only temporary benefits. To achieve long-term durability, we synthesized multifunctional dendrimers containing effective functional groups that impart self-healing capabilities and enhance the power conversion efficiency (PCE). PSCs incorporating these dendrimers achieved a PCE exceeding 25% and retained over 96% of their initial efficiency after 1000 hours under humid conditions. Remarkably, the dendrimer-based PSCs exhibited outstanding self-healing behavior, maintaining 90% of their initial PCE after ten alternating cycles of high-humidity and dry environments. The underlying self-healing mechanism was elucidated, demonstrating the crucial role of the dendrimers as self-healing agents within PSCs.

Interfacial molecules play a pivotal role in achieving high efficiency and durability in perovskite solar cells (PSCs). In this talk, I will introduce our recent progress in designing hole-selective molecules for both n-i-p and p-i-n PSCs, as well as our efforts in discovering novel perovskite surface passivation molecules using generative AI.
For n-i-p PSCs, we designed hole-selective molecules with (1) dual-site anchoring units whose molecular dimensions match the perovskite lattice, and (2) strong dipole moments that enhance interfacial affinity. These molecular designs enable robust interfacial interactions, leading to effective defect passivation, accelerated hole extraction, and improved device stability. For p-i-n PSCs, (3) we developed hole-selective molecules featuring a double donor–acceptor conjugated framework with spatially separated frontier orbitals, allowing strong bifacial binding to both metal oxide substrates and perovskite layers. This strategy significantly enhances both efficiency and operational durability.
Finally, (4) an AI-assisted molecular discovery framework was established by integrating discriminative and generative models based on large language models. Several representative molecules identified through this approach were experimentally validated, demonstrating excellent passivation capability and improved photovoltaic performance in realistic device configurations.

In this study, we present a novel method for controlling the growth of perovskite crystals in a vacuum thermal evaporation process by utilizing a vacuum-processable additive, propylene urea (PU). By co-evaporating perovskite precursors with PU to form the perovskite layer (Figure1), PU, acting as a Lewis base additive, retards the direct reaction between the perovskite precursors. This facilitates larger domain size and reduced defect density. Following the removal of the residual additive, the perovskite layer, exhibiting improved crystallinity, demonstrates reduced charge recombination, as confirmed by time-resolved microwave conductivity analysis. Consequently, there is a notable enhancement in open-circuit voltage and power conversion efficiency, increasing from 1.05 V to 1.15 V and from 17.17% to 18.31%, respectively. The incorporation of a vacuum-processable and removable Lewis’s base additive into the fabrication of vacuum-processed perovskite solar cells offers new avenues for optimizing these devices. This strategy can be extended to other vacuum-processed perovskite compositions and multilayer device architectures, enabling broader applicability of additive engineering in scalable fabrication.

TBA

The presentation focuses on tin-based perovskite (Sn-PVK), which is a promising candidate for the light-harvesting layer in high-efficiency solar cells. Device efficiency has been improved step by step1,2. Stability is another critical issue that must be addressed. Improvements in stability have been achieved by suppressing ion migration from various layers, such as H⁺ diffusion from PEDOT:PSS (HTL), halide ion diffusion from the perovskite layers, and Sn⁴⁺ diffusion from the perovskite3-5. Sn⁴⁺ tends to diffuse toward heterointerfaces when samples are maintained at 85 °C, resulting in decreased efficiency. To prevent Sn⁴⁺ formation, 2-methylaminopyridine (2-MAP) was used instead of DMSO. Stability under light exposure was enhanced by passivating both the top surface and the buried interface using passivation molecules containing ethylenediamine moieties⁶. In conclusion, reducing the concentration of Sn⁴⁺ (via DMSO-free ink), avoiding ionic species (by replacing PEDOT:PSS as the HTL), and suppressing ion diffusion through the use of inorganic layers such as GeOx and ALD-deposited SnOx have all contributed to improved device stability.

In this presentation, we highlight recent advances in Pulsed Laser Deposition (PLD) of metal halide perovskites (MHPs).

We discuss our strategy enabling compositional flexibility, ranging from inorganic to hybrid compounds, as well as polymorph control. These include the transition from polycrystalline to epitaxial monocrystalline layers, the development of 2D/3D heterostructures, and the fabrication of porous scaffolds for hybrid vapor-vapor or vapor-solution growth of wide band gap MHPs.

We draw synthesis, properties, functionality correlations, via the complete characterization of materials and solar cell devices. Our PLD-grown MHPs delivering power conversion efficiencies above 15% as deposited and 19.5% after passivation. We furthermore address the challenges of PLD and present approaches for scaling up this method.

Furthermore, we explore how insights gained from PLD can be transferred to more industry-standard techniques such as sputtering deposition.

Perovskite solar cells (PSCs) have rapidly emerged as leading photovoltaic contenders, achieving power conversion efficiencies (PCEs) exceeding 27% in both p-i-n and n-i-p configurations at laboratory scale.[1] These advancements stem from optimized perovskite compositions, interfacial engineering, and improved charge-transport layers (CTLs).[2, 3] While spin-coating remains the dominant method for fabricating high-efficiency PSCs, its scalability is limited. Transitioning to industrially compatible techniques poses challenges, particularly in depositing ultrathin (10–100 nm) and uniform electron and hole transport layers (ETLs/HTLs).[4-6] Consequently, developing scalable approaches for producing high-quality CTLs remains a critical step toward efficient and stable large-area PSCs.

The choice of transparent conducting oxide (TCO) substrate significantly influences CTL design and deposition. Indium tin oxide (ITO) offers superior transparency and conductivity but relies on scarce indium.[7-9] Fluorine-doped tin oxide (FTO) offers a viable and cost-effective alternative; however, its inherently rougher surface morphology (16–35 nm versus ~0.6 nm for ITO) complicates the deposition of conformal, pinhole-free CTLs by solution processing, often resulting in incomplete coverage and interfacial trap formation.[10, 11] Vacuum-based methods such as magnetron sputtering or atomic layer deposition can overcome these challenges, enabling uniform coatings on textured FTO surfaces.[9]

The predominant solution-based methods for depositing SnO2 films include chemical bath deposition (CBD) and colloidal dispersions.[12-15] Moreover, the ultrathin nature of these films (15–30 nm) makes them prone to pinhole formation, while CBD often requires long reaction times and yields films with uncontrolled oxygen vacancies.[16-18] To address these limitations, vacuum-based techniques such as radio-frequency (RF) magnetron sputtering have gained attention for producing uniform, stoichiometrically controlled SnO₂ layers. This solvent-free process allows the precise control over thickness and composition via sputtering power, deposition pressure, and O₂/Ar ratio.[19, 20]

Despite these advantages, PSCs incorporating sputtered SnO₂ typically achieve PCEs between 13.2% to 20.2%,[21-23] which remains below the 26.4% achieved with solution-based SnO2.[13, 15] This discrepancy is largely due to lower open-circuit voltage (Voc) and fill factor (FF), often attributed to elevated non-radiative recombination rates at the SnO2/perovskite interface.[13, 16] Such recombination is linked to complex surface states and oxygen-related defects generated during sputtering.[24-26]

This study presents a comprehensive evaluation of sputtered SnO₂ thin films, establishing correlations between structural, optical, chemical, and interfacial properties and the resulting PSC performance. By systematically tuning annealing temperature, oxygen concentration, and sputtering pressure, we identified processing windows that yield high-quality SnO₂ with enhanced crystallinity, reduced hydroxylation, optimized band alignment, and low surface recombination velocity (SRV). Target aging was found to significantly alter film stoichiometry and optical characteristics, necessitating oxygen compensation to maintain performance. Optimal conditions, 40% O₂ at 9 mTorr followed by annealing at 450 °C, produced the best films, achieving 20.7% efficiency, among the highest reported for sputtered SnO₂ without additional passivation.

Time-resolved photoluminescence and SRV analyses revealed that optimized sputtered SnO₂ interfaces approach the quality of nanoparticle-based ETLs, demonstrating that controlled vacuum deposition can rival solution-processed benchmarks. Drift-diffusion simulations incorporating experimental SRV and band-alignment data confirmed that interfacial recombination, rather than ETL transport limitations, governs device losses. Overall, this study elucidates how sputtering parameters dictate microstructure, defect chemistry, and energetics, providing clear design principles for scalable, high-performance SnO₂ ETLs .

Recent studies on organic and perovskite optoelectronic devices have primarily relied on solution processing. However, from the perspective of commercialization, the vacuum-deposited process is more feasible because the representative OLED industry is based-on vacuum-deposition process.[1] First, we present the development of wavelength-selective organic small molecules from UV to Red with their application in high-performance optical sensors. For narrowband UV selective organic photodetectors (OPDs), three thiazolothiazole-based small molecules were synthesized as an active layer donor.[2] The extended π-conjugation and highly planar backbone was important to improve the intermolecular ordering and efficient charge transport even in the evaporation with C60 acceptor. The resulting OPDs exhibited high responsivity and detectivity with ultrafast response times and a cutoff frequency. Moreover, the devices were successfully monolithically integrated with CMOS image sensors, enabling multifunctional imaging without resolution loss. For R/G/B wavelength selective OPDs, a series of cyclopentadithiophene-based donor molecules were designed for tuning absorption from blue to red while maintaining low molecular weights and thermal stability suitable for vacuum deposition.[3] When blended with C60, a green-selective donor exhibited outstanding performance with external quantum efficiency (EQE) up to 70% and specific detectivity of 2.5 × 10¹² Jones. These devices demonstrated practical applications in visible-light communication and high-resolution X-ray imaging. Seceond, we report novel bathocuproine (BCP) derivatives for cathode buffer layer in perovskite solar cells (PSCs). Substituting phenyl and p-tolyl groups at the 2,9-positions on BCP improves molecular planarity, protects reactive sites, which significantly enhances charge transport, reduces recombination losses, and markedly improves the structural stability of PSCs.[4] 

The sustainability of perovskite solar cell manufacturing has become increasingly critical as commercialization advances. Thermal evaporation, while providing precise control over film deposition, also generates material waste through leftover precursor in crucibles after each cycle. This study evaluates the feasibility of reusing thermally evaporated electron transport layer (ETL) materials, with no purification or chemical treatment, to address sustainability and cost-effectiveness in perovskite photovoltaics.

Two batches of perovskite solar cells, each consisting of devices with both fresh and reused ETL materials, were fabricated to assess reproducibility. The reused material was collected directly from the thermal evaporation crucible following the first deposition and applied without further processing. This design presents a straightforward approach where only the ETL layer differentiates the test groups, and all other device layers and processing steps remain unchanged. This setup permits direct assessment of whether ETL material reuse impacts device performance and stability, while minimizing extraneous experimental variables.

Device characterization utilized dark current-voltage (IV) measurements to probe charge transport properties and recombination mechanisms. Dark IV analysis reveals critical features such as interface quality, series resistance, and ideality factors, which signal the electronic properties and potential issues associated with the reused ETL. Capacitance-voltage (C-V) profiling assesses charge carrier distribution, built-in potentials, and interfacial properties, while capacitance-frequency (C-F) measurements provide trap density data and insight into defect states. These complementary techniques collectively offer a comprehensive picture of how reused ETL material influences electronic and structural device characteristics.

Device stability was investigated through three distinct methods relevant to real-world operation. Shelf-life stability was tracked by storing devices under inert conditions in a glove box and periodically measuring IV characteristics, providing insight into intrinsic material degradation and interface evolution over time. This protocol reveals stability without external stressors and serves as a baseline for degradation rates. Thermal stability was evaluated by subjecting devices to elevated temperatures to examine degradation pathways and long-term reliability, while Maximum Power Point Tracking (MPPT) stability measurements monitored device performance under continuous operation, simulating actual deployment scenarios.

The strategy demonstrates the implementation of circular economy principles for perovskite solar cell manufacturing. By reusing crucible residues without complex purification, this method addresses material waste and streamlines fabrication. Reproducibility across batches provides strong statistical validation of the protocol. Environmentally, material reuse in perovskite manufacturing is highly beneficial; recent lifecycle assessments report up to 53% reduction in global warming potential through recycling strategies. Thermal evaporation is a particularly suitable process for such recovery due to the absence of solvents and high material purity.

Results from this investigation clarify the link between material reuse cycles and device performance, supporting the development of sustainable production approaches for perovskite photovoltaics. Benchmarks for acceptable performance levels help guide future adoption and scaling of reuse strategies. This study offers a practical framework for ETL material sustainability in thermal evaporation-based perovskite solar cell manufacturing, balancing high device quality with economic and environmental benefits.

Modeling next-generation PV devices, particularly two-terminal perovskite tandem configuration, presents a critical challenge: strong spectral selectivity. The performance of these devices is strongly influenced by spectral variability, which affects the current matching between subcells and, consequently, the overall energy yield. Accurate tandem modeling requires the separate prediction of direct and diffuse components of time-resolved spectral irradiance, which must be fed into optical and electrical simulation tools to determine the limiting photocurrents in each subcell [1]. Furthermore, knowing the subcell currents enables the identification and mitigation of spectral mismatch, which can drive the perovskite subcell into persistent reverse bias conditions, compromising the long-term reliability of tandem devices [2]. Addressing spectral sensitivity on an intra-hourly basis, in addition to improving modeling fidelity due to the data granularity, also enhances energy forecasting in dynamic electricity pricing markets—contexts in which emerging technologies like perovskite tandems are expected to operate. While predicting solar spectra under real sky conditions is inherently complex, most existing approaches rely on clear-sky models. Physical models offer high fidelity but are computationally intensive and impractical for real-time or large-scale applications. In contrast, AI modeling offer computational speed and efficiency, meaning they can deliver accurate spectral predictions with significantly reduced processing time and resource consumption. We present an AI-driven model based on Extra Trees Regression to generate accurate spectral distribution data under clear and cloudy sky conditions. Trained on over two million terrestrial spectra measured continuously over six years in Golden, Colorado, our model captures a high diversity of real-world spectral distributions. It predicts the direct and diffuse spectral distributions using only four readily available meteorological inputs: Air Mass, Clearness Index, Diffuse Fraction, and Precipitable Water. The model achieves high predictive accuracy, with Normalized Root Mean Square Error (NRMSE) mostly below 1% per wavelength and Spectral Angle Mapper under 5%, demonstrating strong spectral similarity and robustness across varying sky conditions. Additionally, our model also exhibits geographical robustness, successfully predicting the spectral distribution in Lima, Peru, a low-latitude site with extreme precipitable water levels compared to the training site.

Two-dimensional (2D) metal halide perovskites have shown promise as materials for a wide range of technology including solar cells, photodetectors, transistors, spintronic devices, memory devices, and ionizing-radiation detectors. The presence of stable excitons at room temperature in 2D perovskites also provides an ideal medium for light-emitting applications and a testbed for exciton physics. 2D perovskites have unique magneto-optical properties which have provided a comprehensive insight into the energy and spin structure of their exciton states. Materials with a strong optical response to external magnetic fields are highly desirable for applications in sensing and photonics, so the ability to tune this response presents a pathway to develop a new class of magneto-optical devices. This presentation will include an overview of magnetic field effects of excitons in 2D perovskites, and their significance in optoelectronics applications. Following this, the latest work using magneto-photoluminescence (MPL) spectroscopy will be presented, showing the influence of both intrinsic and extrinsic factors on the magneto-optical properties of 2D perovskites via modifying the energy splitting between bright and dark excitons. Magneto-optical microscopy reveals localised populations of these states in thin films and single crystals, highlighting the heterogenous nature of exciton emission. Finally, we show how a 15× enhancement in MPL can be achieved in colloidal 2D perovskite nanosheets at room temperature. Our findings provide critical insight into excitons in 2D perovskites and their effect on light-emitting properties. This work is highly relevant for the development of 2D perovskite optoelectronics and paves the way for new applications including magnetometry.

Organo–lead iodide perovskites (PVSKs) have attracted extensive attention owing to their tunable optoelectronic properties, facile fabrication, and low cost. However, incomplete conversion of PbI₂ precursors remains a persistent issue in solution-processed PVSK films, leading to undesirable PbI₂ residues that compromise long-term device stability. In this work, we present a novel precursor engineering strategy in which pre-synthesized MAPbI₃ single-crystal powders are dissolved into conventional coating solvents to form a stoichiometrically balanced precursor solution. This single-crystal-derived approach effectively eliminates residual PbI₂, producing PbI2-free, morphologically uniform and chemically homogeneous MAPbI₃ films with low defect densities. Devices fabricated from these films exhibit a champion power conversion efficiency (PCE) of 21.01%, while 5 × 5 cm² mini-modules achieve 19.8% under AM 1.5G illumination and 39.7% under indoor LED light. In comparison, conventional precursor-based devices deliver lower PCEs of 18.61% (cell) and 17.2% (mini-module) under AM 1.5G illumination, and 34.5% under LED light. Furthermore, single-crystal-derived devices retain 99% of their initial efficiency after 1000 hours of operation in ambient dry-room conditions without encapsulation, whereas conventional devices show significant degradation.

Beyond pure MAPbI₃, this strategy also enables convenient preparation of mixed-halide perovskite films by simply combining different PVSK single-crystal powders in designed proportions. The resulting films remain PbI₂-free and exhibit superior halide uniformity compared with those derived from conventional precursor methods. Consequently, single-crystal-derived mixed-halide PVSK films effectively suppress photoinduced I/Br segregation, leading to enhanced optoelectronic stability and improved device performance.

Defects and voids at the buried interface of perovskite films critically limit charge extraction and reproducibility in self-assembled monolayer (SAM)–based inverted perovskite solar cells (PSCs). In this work, we present a synergistic buried-interface engineering strategy that combines MACl additive regulation and PFN-Br interlayer modification to simultaneously enhance perovskite crystallization and interfacial energetics. Incorporating MACl promotes oriented crystal growth and suppresses interfacial strain, yielding compact films with reduced defect density.^1,2 Complementarily, the introduction of an amphiphilic conjugated polyelectrolyte (PFN-Br) between the MeO-2PACz SAM and perovskite layers effectively covers uncovered ITO regions and mitigates interfacial void formation.^3–5 Conductive AFM and cross-sectional SEM confirm the elimination of buried voids, while photoemission analyses reveal favorable interfacial band bending that facilitates charge separation and suppresses recombination. Consequently, the optimized devices achieve a stabilized power conversion efficiency of 22.5% with an exceptional fill factor of 0.84 and outstanding reproducibility (standard deviation < 0.01). This study highlights that fine-tuning buried interfaces through cooperative chemical passivation and energetic alignment is a key route toward scalable, stable, and high-performance SAM-based perovskite photovoltaics.

Electron-transport-layer-free (ETL-free) perovskite solar cells (PSCs) combine structural simplicity with high efficiency, making them ideal for tandem applications as top cells. While most efforts have improved performance by modifying the fluorine-doped tin oxide (FTO)/perovskite interface, the role of the perovskite/hole transport layer (HTL) interface has been largely overlooked. Here, we enhance charge collection in ETL-free PSCs by tuning the internal electric field through both bulk perovskite optimization and interface engineering [1]. Using excess PbI₂ doping and annealing to control carrier properties, we improve the perovskite’s electronic behavior. A multifunctional 2D-perovskite interlayer further passivates surface defects and introduces a built-in electric field, similar to the n/p/p⁺ back-surface field found in silicon solar cells. Cross-sectional Kelvin probe force microscopy (KPFM) reveals the mechanism of this interfacial field. The optimized devices reach a record 22.47 % power conversion efficiency, without any FTO modification or extra interlayers, and retain 75 % of their performance after 1100 hours in a humid (≈50 ± 5 % RH) dark environment. This work demonstrates a practical route toward efficient, durable, and scalable ETL-free perovskite solar cells.

The growing demand for scalable fabrication of high-efficiency organic photovoltaic (OPV) cells and modules is becoming increasingly evident, particularly in the context of indoor applications. Indoor organic photovoltaics (IOPV) represent a promising energy harvesting solution for powering Internet of Things (IoT) devices, owing to their flexibility, reliability, and high power density under low-light conditions. With billions of IoT devices expected to be deployed in the coming years—many of which will operate within indoor environments—there is a critical need for custom-designed, conformable photovoltaic systems that can adapt to the diverse form factors of devices such as environmental sensors, smart tags, and health monitors.

In this context, inkjet printing has emerged as a particularly attractive technique for the scalable production of flexible OPV cells and modules. This digital, additive manufacturing method enables precise material deposition, minimal waste, and unprecedented freedom in design and geometry, making it ideal for producing PV devices tailored to a wide range of shapes and applications.

Here, we address the key challenge of translating laboratory-scale processes into industrial-scale manufacturing for the realization of fully inkjet-printed, high-efficiency IOPV cells and modules. To highlight the unique advantages of inkjet printing, we demonstrate custom-shaped OPV modules integrated into various IoT devices, enabling autonomous operation without the need for batteries or connection to the electrical grid. This work underlines the potential of inkjet-printed IOPVs as a viable power source for the next generation of smart, connected indoor devices.

All-inorganic CsPbI₂Br perovskite solar cells suffer from interfacial defects and stress-induced instability that limit their performance. [1] Herein, we systematically investigate how annealing parameters—atmosphere, duration, and cooling rate—govern defect formation and stress evolution. Moderate air annealing promotes the formation of Pb–O bonds, effectively passivating surface Pb²⁺ defects and increasing the open-circuit voltage (VOC) to 1.31 V. [2], [3] However, excessive oxidation results in residual compressive stress, which accelerates structural degradation and performance loss during storage. By introducing a slow-cooling process, lattice relaxation is facilitated and the internal stress is reduced from 50.4 MPa to 31.1 MPa, resulting in devices with a power conversion efficiency of 15.3%, fill factor of 80.8%, and remarkable long-term stability, retaining over 95% of the initial efficiency after 600 hours. These findings highlight that a well-balanced combination of oxidation and thermal stress engineering is critical for achieving high-performance and stable CsPbI₂Br photovoltaics.

AgBiS₂ has emerged as a promising, lead-free semiconductor for next-generation thin-film photovoltaics owing to its suitable band gap (0.9-1.0 eV), high absorption coefficient, and excellent environmental stability. In recent years, AgBiS₂ nanocrystal (NCs) based solar cells have shown significant progress in device performance [1]; however, most reported fabrication routes rely on complex nanocrystal synthesis or a multistep ligand-exchange procedure that limits the scalability. To address these challenges, we developed a simple and cost-effective solution-processing method for fabricating AgBiS₂ absorber layers directly from the precursor solution using a one-step deposition method [2]. Using this method, we confirmed the formation of a single-phase, highly crystalline AgBiS₂ porous film without secondary impurities. Optical measurements revealed strong visible-light absorption with a band gap of 0.95 eV, while XPS provided insights into surface composition after its surface engineering. The AgBiS₂ film of about 280 nm AgBiS₂ integrated into SnO₂/AgBiS₂/P3HT heterojunction, achieved an efficiency of 6.3 % with a photocurrent density of 39.2 mA cm^-2, representing the highest reported to date for AgBiS₂ films prepared via a simple solution-based process. The devices exhibited a remarkable operational stability, retaining 6.8% efficiency after 40 min under maximum power point tracking. The external quantum efficiency spectrum reveals strong photoresponse from 300 to 1400 nm, with particularly high absorption in the near-infrared region. Additionally, device studies using SnO₂ as an electron transport layer demonstrated efficient charge separation and a well-defined depletion region at the SnO₂/AgBiS₂ interface, supported by EBIC mapping. These results highlight the potential of AgBiS₂ as a sustainable, solution-processable absorber for environmentally friendly solar cells, paving the way toward scalable optoelectronic technologies.

Organic–inorganic hybrid perovskites have recently emerged as compelling candidates to replace conventional semiconductors, driven by a suite of remarkable optoelectronic properties. These include broadband light absorption, tunable band gaps, high charge-carrier diffusion lengths, solution-processability at low cost, and intrinsic mechanical flexibility. However, their commercial viability is critically hindered by poor environmental stability—particularly their susceptibility to moisture, thermal stress, and photodegradation—as well as the toxicity associated with water-soluble lead compounds, posing significant ecological and health-related challenges. Substituting Pb²⁺ with homovalent (Sn²⁺, Ge²⁺) or heterovalent (Sb³⁺, Bi³⁺) cations effectively mitigates toxicity while preserving perovskite functionality. Notably, vacancy-ordered layered double perovskites (LDPs) (A₄M(II)M(III)₂X₁₂) emerged recently as a promising lead-free class, offering direct band gaps, enhanced stability, and tunable optoelectronic properties via precise divalent/trivalent cation engineering. In this study, we conducted a systematic investigation into M(III) cation engineering within the Cs₄CoIn₂Cl₁₂ LDP framework by substituting In³⁺ with Bi³⁺ and Sb³⁺. This strategy facilitated the first-ever colloidal synthesis of Cs₄CoBi₂Cl₁₂ and Cs₄CoSb₂Cl₁₂ NCs. We examined how the structural distortions arising from these substitutions influence the optoelectronic properties of these NCs, revealing that Cs₄CoBi₂Cl₁₂ exhibited superior performance, characterized by a stable photo response and enhanced photocurrent generation in photoelectrochemical (PEC) applications. Transient absorption analysis confirmed the highest population of self-trapped excitons (STEs) alongside the longest half-lifetime in Cs₄CoBi₂Cl₁₂ hosts, enabling it as a promising material for sustainable PEC applications. Additionally, all the NCs demonstrated remarkable air and compositional stability, preserving their structural and chemical integrity for over 100 days under ambient conditions.

The selective conversion of biomass-derived molecules into high-value chemicals under mild and sustainable conditions remain a challenge in the field of green chemistry and renewable energy. Among various bio-based platform compounds, 5-hydroxymethylfurfural (HMF), which can be readily obtained from the dehydration of hexose sugars, has emerged as an intermediate to produce a variety of value-added chemicals and polymer precursors. However, achieving high selectivity and efficiency in its oxidative transformation under ambient conditions continues to be highly challenging due to the complex reaction pathways and low stability of conventional catalysts. In this study, we report a highly efficient photocatalytic system consisting of CsPbBr₃ perovskite supported in hollow spheres of titanium dioxide (TiO₂). This kind of system improves visible light absorption, efficient charge separation, and enhanced stability of the perovskite under reaction conditions. Under visible light irradiation, the hybrid catalyst enables the selective oxidation of 5-hydroxymethylfurfural (HMF) to both 2,5-diformylfuran (DFF) and 2,5-furandicarboxylic acid (FDCA), two major platform chemicals to produce bio-derived polymers. Mechanistic studies reveal that the synergistic interaction between the CsPbBr₃ and TiO₂ facilitates the generation of reactive oxygen species and directs the oxidation pathway. This work demonstrates a powerful strategy for integrating halide perovskites into functional photocatalytic systems for sustainable biomass enhancement under visible light.

Metal halide perovskites (MHP) have emerged as an apposite semiconductor material for various optoelectronic devices such as solar cells, photodetectors, capacitors, sensors etc. Despite the ample possibility, metal halide perovskites including bismuth have not been explored for NH₃ production. We have utilized bismuth-based perovskites as an electrocatalyst for reduction of nitrate to ammonia. We report fabrication of methylammonium bismuth iodide ((CH₃NH₃)₃Bi₃I₉) MABI) thin film directly on fluorine doped tin oxide (FTO) substrate and detailed structural, morphological and optical properties of the thin film reveal the formation of interconnected pure hexagonal structure with band gap of ~ 2.1 eV. The as-fabricated MABI thin film showed outstanding ammonia yield (27.53 µg mg⁻¹ h⁻¹) under atmospheric conditions with exceptional Faradic efficiency (40%). This work not only describes direct conversion of nitrate to ammonia under mild conditions employing lead-free non-toxic MABI but also, use of nitrate ions which are carcinogenic to human beings and major water pollutants as nitrogen source. Thus, in addition to green ammonia production this electrocatalytic process also paves the way to control nitrate pollution. The findings demonstrate the potential of hybrid halide bismuths in addressing the dual challenges of energy efficiency and environmental sustainability in nitrogen fixation. Future work focusing on the optimization of structural properties and scalability could further advance the practical applications of this material in green ammonia synthesis. This study paves the way for the exploration of novel lead-free perovskite materials in catalytic systems, contributing to the global shift towards sustainable chemical processes and a potential technology for low temperature, low pressure ammonia production.

The silicon photovoltaic industry has matured significantly over the past decades and there is a general consensus that future breakthroughs will require novel photovoltaic absorbers to enhance the performance of silicon in tandem solar cells, which comprise stacks of multiple absorber layers. Lead halide perovskites are currently receiving considerable attention for application in commercial silicon–perovskite tandem solar cells. However, concerns regarding their intrinsic stability and toxicity provide strong motivation to explore alternatives beyond lead halide perovskites, seeking photovoltaic absorbers that can similarly enhance silicon performance. A vast fraction of the approximately 10 billion possible inorganic materials remains unexplored. This represents an excellent opportunity for the discovery of novel photovoltaic materials, but it also poses equally daunting challenges: namely, the identification of promising PV material candidates in silico and their efficient experimental validation in situ. This presentation will examine these challenges in more detail and introduce a novel autonomous experimental materials discovery platform, established in Melbourne (Australia), designed specifically for the evaluation of novel solution-processable PV absorber materials. The platform consists of multiple collaborating robotic units capable of (1) formulating coating inks from solid and liquid precursors, (2) fabricating thin films from these coating inks, and (3) performing comprehensive analysis of these thin films with respect to their structural, optical, and electrical properties. Figure 1 provides a schematic overview of the materials discovery workflow. In the 2^nd part of this talk I will discuss challenges and opportunities associated with photoinduced halide dynamics in lead halide perovskites.

The performance of perovskite solar cells (PSCs) is critically dependent on the morphology and crystalline quality of the light-absorbing perovskite film. Dimethyl sulfoxide (DMSO), a high-boiling-point polar solvent, is widely used to prepare high-quality perovskite films due to its strong coordination with lead-iodide bonds. However, the slow evaporation kinetics make it challenging to control crystal nucleation and growth, often leading to inhomogeneous crystallization and buried interfacial pinholes, which ultimately limit device efficiency and stability.

To overcome these challenges, we developed a series of DMSO extraction engineering strategies to precisely regulate solvent removal pathways during perovskite crystallization. First, a polar bifunctional molecule was introduced to achieve dual-side passivation of the buried interface, effectively suppressing DMSO adsorption on unsaturated defect sites and facilitating its complete volatilization.^[1] Second, an ultrafast photo-responsive molecule was designed, whose sub-picosecond, UV-induced isomerization actively propels DMSO molecules away from the bottom interface of the perovskite layer.^[2] In addition, a zwitterionic elastomer was incorporated into the perovskite precursor solution, which selectively adsorbs DMSO and self-assembles along grain boundaries, guiding an ordered DMSO release that ensures uniform and defect-suppressed crystallization across the film.

These findings highlight the importance of solvent management in perovskite crystallization and provide a materials-based route toward high-efficiency and stable device fabrication.