Pnictogen Based Perovskite Inspired Photovoltaics and Emerging Applications

G. Krishnamurthy Grandhi^a

^aHybrid Solar Cells, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33014 Tampere University, Finland

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

A4 Emerging Hybrid and Inorganic Solar Absorbers: Beyond ABX3

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Nakita Noel, Jay Patel and Marcello Righetto

Invited Speaker, G. Krishnamurthy Grandhi, presentation 610
Publication date: 15th December 2025

Pnictogen-based perovskite-inspired materials (PIMs) incorporating Bi and Sb have emerged as promising low-toxicity alternatives to lead halide perovskites, combining environmental stability with rich structural and electronic tunability. In this talk, I will present how we combine compositional and crystal-chemistry design with thin-film processing and device engineering to realize efficient photovoltaics from this family of compounds, and how the same structural motifs also enable emerging functional responses.

I will first focus on Bi- and Sb-based systems such as vacancy-ordered compositions and Cu₂AgBiI₆, showing how compositional engineering and dimensionality tuning can transform quasi-0D semiconductors into more quasi-2D-like absorbers with improved charge transport and competitive outdoor/indoor PV performance[1–3]. I will then discuss our recent outcome in hybrid Sb–Bi halide architectures, where tailored compositions and interfacial control allow perovskite-inspired devices to surpass the 10% efficiency threshold under 1000 lx[4]. Throughout, I will highlight structure–property relationships that link pnictogen–halide connectivity and local structural distortion (bond-angle variance, octahedral distortion) to performance gains, including improved operational stability[5,6].

In the final part, I will show how the same local-structure degrees of freedom—particularly inversion-symmetry breaking and polar nanoregions driven by cation vacancies and compositional tuning—enable emerging functionalities in Bi PIMs. Using Cu–(Ag)–Bi–I systems as model materials, I will demonstrate how nonlinear optical microscopy reveals robust second-harmonic generation, with a stronger response in the vacancy-rich Cu-based composition[7], and point towards multifunctional optoelectronic behavior in pnictogen-based PIMs beyond conventional ABX₃ halide perovskites.

References:

[1] Grandhi G K, Al-Anesi B, Pasanen H, Ali-Löytty H, Lahtonen K, Granroth S, Christian N, Matuhina A, Liu M, Berdin A, Pecunia V and Vivo P. Enhancing the Microstructure of Perovskite-Inspired Cu-Ag-Bi-I Absorber for Efficient Indoor Photovoltaics Small 2022, 18, 2203768.

[2] Lamminen N, Grandhi G K, Fasulo F, Hiltunen A, Pasanen H, Liu M, Al-Anesi B, Efimov A, Ali-Löytty H, Lahtonen K, Mäkinen P, Matuhina A, Muñoz-García A B, Pavone M and Vivo P. Triple A-Site Cation Mixing in 2D Perovskite-Inspired Antimony Halide Absorbers for Efficient Indoor Photovoltaics. Advanced Energy Materials 2023, 13, 2203175.

[3] Krishnaiah M, Singh K, Monga S, Tripathi A, Karmakar S, Kumar R, Tyrpenou C, Volonakis G, Manna D, Mäkinen P, Adarsh K V, Bhattacharya S, Grandhi G K, Rao K D M and Vivo P. Perovskite-Inspired Cs₂AgBi₂I₉: A Promising Photovoltaic Absorber for Diverse Indoor Environments. Advanced Energy Materials 2025, 15 2404547.

[4] Lamminen N, Lahtinen J, Krishnaiah M, Karlsson J, Saju M, Grandhi G K and Vivo P. Surpassing the 10% Efficiency Threshold in Perovskite-Inspired Indoor Photovoltaics. ACS Energy Lett. 2025, 10, 3415–8.

[5] Al-Anesi B, Grandhi G K, Pecoraro A, Sugathan V, Viswanath Noolu S M, Ali-Löytty H, Liu M, Ruoko T-P, Lahtonen K, Manna D, Toikkonen S, Muñoz-García A B, Pavone M and Vivo P. Antimony-Bismuth Alloying: The Key to a Major Boost in the Efficiency of Lead-Free Perovskite-Inspired Photovoltaics. Small 2023, 19, 2303575.

[6] Lamminen N, Karlsson J, Kumar R, Viswanath N S M, Lal S, Fasulo F, Righetto M, Krishnaiah M, Lahtonen K, Tewari A, Katerski A, Lahtinen J, Acik I O, Johansson E M J, Muñoz-García A B, Pavone M, Herz L M, Grandhi G K and Vivo P. The Promise of Operational Stability in Pnictogen-Based Perovskite-Inspired Solar Cells. EES Sol., 2025, 1, 139-156.

[7] Annurakshita S, Grandhi G K, Manikanta Viswanath N S, Pecoraro A, Schildt M, Toikkonen S, Muñoz-García A B, Pavone M, Huttunen M J and Vivo P. Structural-disorder-induced enhancement of second-harmonic generation in bismuth-based perovskite-inspired materials. Newton 2025, 1, 100056.

Acknowledgements:

This work was supported by the SPOT-IT project, funded under the 2022 CETPartnership Joint Call for Research Proposals, as part of the Clean Energy Transition Partnership (CETPartnership), co-funded by the European Commission (Grant Agreement No. 101069750). Details of the participating funding organizations are available at https://cetpartnership.eu/funding-agencies-and-call-modules. This work has received funding from the European Union’s Horizon Europe research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 101169056.

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