The transition of perovskite photovoltaics toward industrial roll-to-roll (R2R) manufacturing relies on scalable deposition routes and ink formulations capable of ensuring uniformity, mechanical resilience, and long-term stability. Building on recent advances in tailored perovskite inks for scalable processes and the mechanistic insights into flexible device robustness (1), in this study we demonstrate the successful roll-coating of one-meter-long perovskite films on polymeric substrates with high morphological uniformity.

Using a pre-industrial roll-coater engineered to emulate continuous R2R operation, we optimize roll speed, slot die coating parameters, solution rheology, and gas quenching to obtain perovskite layers with thickness uniformity of 550nm along the full meter. These process conditions, aligned with guidelines emerging from our recent studies on scalable ink rheology and interfacial engineering, enable reproducible film formation with suppressed defect formation and controlled crystallization dynamics (2). Compared to batch-processed references, roll-coated perovskite layers show delayed crack initiation and improved adhesion to transport layers. This behavior is consistent with recent observations on mechanically tolerant perovskite microstructures and elastomer-modified interfaces (3) (4). Overall, this work represents the first demonstrations of meter-scale perovskite deposition via roll coating, linking advanced ink design, scalable processing, and mechanical robustness. The results provide a practical framework to accelerate the translation of perovskite solar technologies toward continuous, industrially relevant R2R fabrication of flexible devices.

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Flexible perovskite solar cells (f-PSCs) require simultaneously high optoelectronic quality and mechanical robustness, yet achieving both remains challenging due to defect-mediated non-radiative recombination and crack formation under strain. Here, we introduce a novel additive to enhance both radiative efficiency and mechanical durability in flexible perovskite devices. Incorporating a novel additive results in improved film homogeneity and a modest increase in grain size. Steady-state PL and PLQY measurements reveal nearly a threefold enhancement in radiative recombination efficiency, directly correlating with the increase in device V_OC. ​Despite similar ionic densities confirmed by rapid hysteresis and BACE measurements, the novel additive-modified devices exhibit moderately improved operational stability, attributed primarily to morphological improvements rather than ionic effects.  Fully encapsulated f-PSCs with polymer maintain 85% of their initial PCE after 10,000 bending cycles, compared to only 38% for the control. Notably, we report, for the first time, in situ J–V measurements performed during active bending, revealing catastrophic FF and Jsc ​ losses in the control, while novel additive-based devices remain largely intact. Overall, this work demonstrates that additive engineering simultaneously enhances radiative efficiency and mechanical resilience, offering a simple and effective pathway toward durable, high-performance flexible perovskite solar cells.

Scaling high-performance perovskite solar cells (PSCs) into large-area photovoltaic modules remains a central challenge due to difficulties in achieving uniform crystallization, suppressing defect-mediated recombination, and ensuring long-term stability. We present a seed-primed and vacuum-assisted crystallization (S-VAC) strategy that enables the fabrication of highly uniform, monolithic perovskite films over 15×15 cm² substrates without the use of anti-solvents. Oleylamine-induced α-phase nanocrystal seeds are formed directly in solution and preserved during low-pressure vacuum processing, which accelerates solvent extraction and drives vertically aligned (100)-oriented crystal growth. In situ GIWAXS measurements reveal a rapid α-phase transition under vacuum, while solution/solid-state NMR and particle-size analysis confirm controlled nanocrystal seed formation prior to film deposition. Cross-sectional TEM and nanoscale infrared PiFM further verify monolithic grain structures, enhanced vibrational ordering, and improved lattice coherence across the film thickness.

These structural advantages translate directly into enhanced optoelectronic performance. Optimized p-i-n devices achieve a power conversion efficiency (PCE) of 23.25% for 2.5×2.5 cm² cells, with high external quantum efficiency across 350–850 nm. Scaled mini-modules fabricated using a laser-scribed P1–P2–P3 interconnection design deliver a certified PCE of 19.1% over a 15×15 cm² aperture, establishing a new benchmark among anti-solvent-free perovskite modules. Electrochemical impedance spectroscopy and TRPL analyses indicate reduced trap-assisted recombination and enhanced carrier lifetimes in S-VAC films, while depth-profile XPS confirms more stable Br-rich surface compositions that mitigate light-induced halide migration.

Long-term operational assessments following ISOS protocols demonstrate excellent stability. Encapsulated modules retain over 94% of their initial efficiency after 500 h of indoor light soaking and maintain stable power output for more than one year of continuous outdoor exposure. Collectively, these results establish S-VAC as a scalable, industrially compatible crystallization route for high-efficiency and durable perovskite photovoltaic module manufacturing.

Perovskite solar cells are emerging as promising candidates for next-generation solar cells and are being extensively researched due to their rapidly increasing power conversion efficiency. However, high-efficiency perovskite solar cells typically use expensive metals such as gold and silver as electrodes, which undermines their cost advantage and limits their applicability due to the complexity of the deposition processes. To address these challenges, researchers have attempted to use carbon film electrodes; however, their performance generally falls short compared to metal counterparts. In this study, we incorporated a self-assembled hole-selective bilayer into a conventional n-i-p perovskite solar cell with a free-standing carbon electrode, enhancing interfacial contact and promoting efficient hole extraction to the carbon electrode. The resulting device exhibited a higher power conversion efficiency of 24.25 %, enhanced stability, and improved reproducibility compared to the control device. [1] Future flexible and scalable perovskite solar cells are anticipated to use the free-standing carbon electrode developed in this study.

Perovskite solar cells (PSCs) can achieve high power conversion efficiency (PCE) in both standalone devices and tandem architectures. Particularly in this latter configuration, PCE values range from 23% to 35% depending on the bottom device (organic, chalcogenide, silicon). Silicon-based tandem devices offer high performance but must be produced on rigid substrates; chalcogenide- and organic-based tandem devices, on the other hand, enable implementation on flexible substrates. Indeed, chalcogenide-based bottom devices are well-suited to meet the requirements of PSCs production. Unfortunately, the most performing chalcogenides have other limitations, such as high prices and poor component repeatability (Cu(In,Ga)S₂) or high toxicity (CdTe). But kesterite can offer a way out: it is a chalcogenide composed of earth-abundant, non-toxic elements, exhibits high stability, and has a tunable bandgap. Among them, Cu₂ZnSn(S,Se)₄ (CZTSSe), with a band gap of about 1.1 eV, is an ideal bottom-cell candidate for tandem devices with perovskites. However, if kesterite can offer low cost and high component availability, the non-outstanding stand-alone device performance (below 16%) still limits advancement in CZTSSe/perovskite tandem.

This study introduces an efficient solution-processed route for fabricating CZTSSe bottom cells on both rigid soda-lime glass (SLG) and flexible molybdenum foil substrates. Incorporating sodium and partially substituting copper with silver enhanced the absorber’s morphology and grain growth, resulting in high-quality thin films. The architecture of the 4-terminal (4T) tandem devices was refined by pairing these optimized kesterite bottom cells with semi-transparent perovskite top cells. Perovskites with various band gaps and compositions were also explored to achieve optimal bandgap alignment between the two subcells and broaden the usable spectral range. Efficiencies above 20% were obtained for both rigid and flexible 4T tandems, highlighting the strong compatibility of these two thin-film photovoltaic materials. Therefore, fabrication of 2-terminal tandem devices has begun, with a focus on optimizing those produced on flexible substrates. The results are encouraging and should spur the search for low-cost and easily produced materials for tandem applications in integrated photovoltaics.

Indium tin oxide (ITO) remains a benchmark transparent conductive material for semi-transparent perovskite solar cells (ST-PSCs), while silica (SiO₂) coatings enhance device performance through strong anti-reflective properties that improve photon absorption. This study explores the controlled optimization of RF-sputtered SiO₂ films and proposes a room-temperature SiO₂/ITO stacked transparent contact to avoid the high-temperature (>200 °C) processing typically required for high-quality ITO. The optimized stack delivers an average visible transmittance of ~90% (400–1000 nm) and a sheet resistance below 45 Ω/sq, with industrial-scale deposition demonstrated on 4-inch silicon substrates. Films sputtered at low pressure (2 mTorr) and low RF power (100 W) exhibit compact, uniform morphologies with surface roughness below 1 nm, supported by XRD, XPS, TEM, AFM, and Hall effect analyses. Notably, dust accumulation decreases with higher oxygen content in the SiO₂ films, revealing inherent anti-soiling tendencies beneficial for outdoor applications. These findings establish a cost-effective pathway for fabricating transparent conductive oxide layers on temperature-sensitive substrates, advancing the development of scalable, flexible, and efficient optoelectronic devices.

Recent breakthroughs in vacuum-based thin-film engineering have unlocked a new generation of fully evaporated perovskite solar cells (PSCs) and photodetectors (PDs) that combine high performance with exceptional uniformity, stability, and manufacturability. By leveraging precisely tuned co-evaporation and buried-interface engineering, we achieve ultrathin, pinhole-free perovskite layers with remarkably low dark current density, a broad linear dynamic range, and outstanding imaging uniformity—key attributes for next-generation multispectral imagers and scalable photovoltaic modules.

Our latest advances demonstrate all-vacuum-deposited hybrid PSCs incorporating a bipolar-host-modified CuPc interface, delivering sustained operational stability with T₁₀₀ > 400 h under continuous illumination [1]. We further uncover how buried-interface energetics dictate crystallization, suppress non-radiative recombination, and govern photostability in vapor-deposited perovskites [2]. Importantly, our all-inorganic vacuum-evaporated perovskites with a 0D passivation architecture enable >42% indoor power conversion efficiency at 600 lux (TLD 840), highlighting their transformative potential for self-powered IoT and low-light energy-harvesting systems.

In parallel, our fully evaporated PDs on ITO achieve a specific detectivity of ~10¹³ Jones in the visible region [3], surpassing conventional Si-based detectors and showcasing the competitiveness of vacuum-grown perovskite optoelectronics for high-sensitivity, low-noise imaging. This presentation will highlight an integrated roadmap for vacuum-processed perovskite electronics—from fundamental physics and interface design to scalable device architectures—revealing a unified platform capable of powering future energy-harvesting systems and enabling ultra-low-light detection across large areas.

Perovskite photovoltaics are entering early commercial markets, yet meeting global energy targets requires scalable, low-cost manufacturing beyond laboratory processes. Roll-to-roll (R2R) fabrication offers a viable path toward high-throughput, large-area deployment. Here, we demonstrate the first fully R2R-manufactured back-contact perovskite modules on embossed flexible polymer substrates, enabling device architectures that are entirely free of rare metals (e.g., Ag, Au) and traditional transparent conductive oxides such as ITO. [1]

Building on previous work reporting cascaded series-connected microgroove devices with record back-contact efficiencies of 12.8% we scale the concept to monolithically processed modules in which every layer is fabricated on a continuously moving web. [2,3] Large-area (>100 cm²) flexible modules achieve >10% power conversion efficiency, representing a step-change in the manufacturability and size of back-contact perovskite technology. The devices incorporate over 55,000 parallel-connected microgrooves, enabling high current output, strong bifaciality, and enhanced tolerance to oblique illumination, unlocking applications such as agri-PV and building-integrated photovoltaics.

To elucidate the optoelectronic behaviour of the microgroove architecture, we combine computational groove simulations with ray-traced optical modelling, revealing spatial charge-generation profiles under varying incident angles. Devices exhibit promising operational stability aligned with ISOS protocols, including accelerated light soaking, damp-heat exposure, and up to five months of outdoor testing. Complementary nanometre-resolution X-ray fluorescence mapping under extreme stress conditions provides insight into degradation pathways in MAPbI3-based back-contact architectures.

Finally, we fabricate R2R modules up to 2,400 cm², delivering instantaneous power outputs and demonstrating the scalability of the technology. These results establish a commercial pathway for low-cost, high-volume production of flexible back-contact perovskite modules.

Silicon solar cells currently dominate satellite power systems; however, they are expensive to manufacture and account for a substantial portion of the total satellite cost, thereby limiting the broader accessibility of space technologies. Given the sharp rise in satellite launches over the past five years, the sector is entering a period of exceptionally high demand. Perovskite solar cells (PSCs) offer a lightweight, low-cost alternative with high power conversion efficiencies and are emerging as strong candidates for next-generation space photovoltaics [1,2].

In this presentation, I will focus on the fabrication of slot-die-coated perovskite films on flexible plastic substrates using two annealing approaches: conventional conductive (hot-plate) annealing and rapid radiative annealing via intense pulsed light (IPL) [3]. The latter aims to accelerate scale-up and enable fast, continuous manufacturing of flexible PSCs. A comprehensive investigation of material and device properties was performed, revealing notable differences between the two approaches. Furthermore, the radiation tolerance of the resulting devices was assessed under ionizing radiation to evaluate their suitability for future space applications [4,5].

Hot-plate annealing relies on high-temperature ovens and long conveyor systems, which result in slow throughput and increased production costs. In contrast, IPL annealing delivers millisecond-scale thermal processing, enabling rapid, energy-efficient, and inline-compatible fabrication that is well suited for large-area production. The results show that IPL-annealed films exhibit enhanced structural and optoelectronic properties while achieving device performance comparable to, or potentially exceeding, that of conventionally annealed counterparts.

The performance of both hot-plate and IPL-annealed PSCs was evaluated before and after exposure to ionizing radiation, and the resulting degradation mechanisms were systematically analyzed.

Perovskite solar cells (PSCs) have attracted intensive attention due to the high power conversion efficiency and solution-based fabrication process. To assemble efficient PSCs, we have designed and synthesized various additives including both small molecules and polymers to tune the properties of the perovskite layer and charge transport layers. For the latest results, we have fabricated PSCs with efficiencies exceeding 27.3% by constructing 2D perovskites at the buried interface, while simultaneously passivating defects in the bulk and on the surface of the 3D perovskite layer. For stability, we have investigated the ion migration/diffusion phenomenon within the perovskite films and across interfaces, and developed techniques to suppress the undesired ion movement. Furthermore, we extend the application of PSCs to flexible formats using low-temperature, vapor-assisted deposition on polymer substrates. This approach enables the successful fabrication of 30 × 30 cm² flexible PSC modules, where interface engineering significantly improves both photovoltaic performance and operational stability.

Flexible perovskite solar cells promise lightweight and conformable photovoltaics, but their scalability is limited by low thermal budgets, strained interfaces and stability challenges. In this talk, I will present our recent work on Flash Infrared Annealing (FIRA) as an ultrafast, low-temperature route to fabricate efficient and stable flexible perovskite devices. Sub-second FIRA processing enables rapid solidification of FAPbI₃-based films on polymer substrates, yielding dense microstructures and controlled crystallographic texture. By tailoring the FIRA pulse profile, we induce a strain-stabilized tetragonal FAPbI₃ phase without relying on heavy compositional alloying, and relate this to charge transport and non-radiative recombination at the perovskite/transport-layer interfaces.

I will also briefly discuss our recent FIRA-enabled high-temperature sintering of TiO₂ photoanodes on ultra-thin ITO/polyimide foils for ultralight dye-sensitized solar cells, demonstrating the generality of FIRA for compatible hybrid photovoltaics.

The FIRA process is integrated with flexible-compatible charge-transport layers, passivation schemes and encapsulation, and we assess both operational and mechanical stability under illumination, bias, and temperature. These results position FIRA as a promising platform for scalable manufacturing of flexible perovskite solar cells.[1],[2]

Ambient-air fabrication of flexible perovskite solar cells (f-PSCs) is a crucial step toward scalable and cost-effective commercialization. However, achieving high photovoltaic efficiency, long-term operational stability, and mechanical robustness under high-humidity conditions remains challenging, as moisture-induced defects at both the buried and top interfaces severely deteriorate device performance. Here, we present a stepwise defect passivation strategy using phenethylammonium chloride (PEACl) to form two-dimensional (2D) halide perovskite layers at both the buried and top perovskite interfaces, enabling the fabrication of efficient and highly durable f-PSCs under relative humidity (RH) conditions of up to 50%. Incorporation of 2D perovskite into the hole-transport layer (HTL) enhances moisture resistance and interfacial stability simultaneously. The resulting f-PSCs exhibit a flexible-to-rigid efficiency ratio exceeding 94% and retain 85% of their initial efficiency after 2,800 hours of air storage without additional encapsulation. Furthermore, dual-sided 2D passivated f-PSCs demonstrate outstanding mechanical reliability, maintaining 96% of their initial efficiency after 10,000 bending cycles and 87% after extreme shear-sliding tests. These results highlight the potential of 2D perovskite engineering to enhance both mechanical and environmental stability in f-PSCs and overcome key barriers to their large-scale manufacturing under ambient conditions.

Carbon-electrode perovskite solar cells (C-PSCs) are attractive for scalable and low-cost photovoltaics, yet their performance and durability are often limited by suboptimal hole-transport interfaces and strain-induced defects, especially in flexible devices. Here we report a combined interface–mechanics engineering strategy to unlock efficient and endurable rigid and flexible C-PSCs.

First, we regulate the molecular orientation of semicrystalline P3HT hole-transport layers (HTLs) from the conventional edge-on packing to a three-dimensional (3D) oriented configuration via a synergistic additive/solvent approach. This orientation transition suppresses alkyl-chain–dominated contact at the perovskite/HTL interface, improves energy-level alignment, and enhances interfacial charge extraction and moisture tolerance. As a result, carbon-electrode devices deliver power conversion efficiencies (PCEs) up to 20.55% (0.04 cm²) and 18.32% (1 cm²), ranking among the highest for C-PSCs.[1]

Building on the oriented-HTL platform, we further develop a strain-compensation strategy for flexible carbon-electrode PSCs by depositing a hot HTL solution onto the perovskite film. This process converts detrimental tensile strain into benign compressive strain, promotes ordered HTL molecular arrangement, optimizes interfacial energetics, and passivates defects. The synergistic effects suppress non-radiative recombination and accelerate hole transport, enabling PCEs of 20.91% for rigid C-PSCs and 19.52% for flexible devices. The flexible cells exhibit excellent environmental and mechanical stability, retaining ~75% of initial efficiency after 1000 bending cycles at an 8 mm radius.[2]

Overall, our work highlights how molecular packing control and strain engineering can be co-designed to deliver high-efficiency, scalable, and robust carbon-electrode perovskite photovoltaics for portable and flexible green-energy applications.

In recent years, the integration of emerging perovskite solar cells with traditional crystalline silicon (c-Si) solar cells to construct perovskite/silicon tandem devices has become a promising photovoltaic technology. However, the integration of commercial silicon cells with perovskite solar cells, particularly on textured silicon substrates featured with large pyramids (2~5μm), presents a significant challenge for achieving effective charge transfer, which is critical for highly efficient tandem solar cells. To address this challenge, this report highlights our recent research progress in molecular-scale nanotechnology. By designing the interface structure of the charge transport layer and optimizing the crystallization process of perovskite on textured silicon substrates, we have fabricated uniform, dense and high-quality perovskite films on the surface of silicon cells with a rough texture. Based on this, we developed highly efficient perovskite/silicon tandem solar cells with certified power conversion efficiency exceeding 34%. This series of research aims to systematically enhance the performance of perovskite/silicon tandem photovoltaic devices and push its industrial application.