Role of Ultrathin Oxide Interlayer in Stable and Scalable NIR Transparent Wide Bandgap Perovskite Solar Cells

Venkatesh Gangareddy Chityala^a, Laxmi Laxmi^b, Tulsiram Moodalabeed Prasannakumar^c, Abhijit Singha^b, Subir Manna^b, Chander Mohan^b, Sudhanshu Mallick^a, Dinesh Kabra^b^,^c

^aMetallurgical Engineering & Materials Sciences, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.

^bPhysics, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.

^cAdvanced Renewable Tandem-Photovoltaics (ART-PV) India Private Limited, Society For Innovation & Entrepreneurship (SINE), Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.

Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV26)

Uppsala, Sweden, 2026 May 18th - 20th

Organizers: Gerrit Boschloo, Ellen Moons, Feng Gao and Anders Hagfeldt

Poster, Venkatesh Gangareddy Chityala, 184
Publication date: 11th March 2026

Near-infrared transparent (NIRT) wide bandgap perovskite solar cells (PSCs) are promising top sub-cells for perovskite/silicon tandems, but their scalability and stability remain major challenges. Two-terminal (2T) tandems require strict current matching, whereas four-terminal (4T) architectures allow independent operation, making them more suitable due to different stability lifetimes of perovskite and silicon sub-cells.^[1] In this work, we address the scalability of p-i-n PSCs through interface passivation, absorber thickness optimization, and transparent conducting electrode (TCE) design.^[2] By introducing an ultrathin Al₂O₃ interlayer in wide-bandgap devices, we achieved efficiencies of 20.20% on 0.056 cm², and of 20.28% on 0.175 cm² with operational lifetimes exceeding T₈₀ > 1600 h. We further scaled the devices to ~1 cm²by employing thicker perovskite absorbers and metallized TCEs to reduce resistive losses. Building on this, we successfully demonstrated single pixel PSC devices with an active area ~ 5 cm² in both opaque and NIRT configurations, underlining the scalability of our approach for commercialization and perovskite/silicon tandem applications.

References:

[1] K. Hossain, S. Nayak, D. Kabra, Appl Phys Lett 2024, 125, DOI: 10.1063/5.0232621.

[2] L. Laxmi, V. G. Chityala, S. Nayak, A. Paul, S. Gupta, M. Misra, K. Hossain, M. K. Singh, S. Mallick, D. Kabra, Solar RRL 2025, 9, DOI: 10.1002/solr.202500163.

Acknowledgements:

The authors gratefully acknowledge the support of the National Centre for Photovoltaic Research and Education (NCPRE) – Phase III, and Advanced Renewable Tandem-Photovoltaics (ART-PV) India Private Limited, Society for Innovation & Entrepreneurship (SINE), supported by the Ministry of New and Renewable Energy (MNRE), Government of India, for its assistance. Thankful to IIT Bombay for providing fabrication and characterization Central facilities. The authors are additionally grateful to all members of the Hybrid Optoelectronics Devices (HOD) Lab for their valuable contributions and support.

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