Double ETL Architecture for Ambient-Air Fabrication of Green-solvent based FAPbI3 Perovskite Solar Cell

Hamed Rahbari^a, Hafez Nikbakht^a, Fabio Matteocci^a, Daimiota Takhellambam^a, Mariia Tiukhova^a, Abhishek Kumar Chauhan^a, Luigi Vesce^a^,^b, Aldo Di Carlo^a^,^b

^aCHOSE – Dept. Electronic Engineering University of Rome Tor Vergata, Casale 11, Rome, 00133 Italy

^bCNR-ISM Istituto di Struttura Della Materia, Consiglio Nazionale Delle Ricerche, Roma Tor Vergata, Rome, 00133 Italy

NIPHO25
Proceedings of International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics (NIPHO25)

Cagliari, Italy, 2025 June 9th - 10th

Organizers: Giulia Grancini, Daniela Marongiu and Aldo Di Carlo

Poster, Hamed Rahbari, 028
Publication date: 24th April 2025

Perovskite solar cells (PSCs) offer high efficiency and low-cost fabrication, but their reliance on inert-atmosphere processing and high-temperature ETL formation limits scalability. Most high-efficient and stable PSCs with the conventional n–i–p (normal) architecture employ a combination of compact and mesoporous TiO₂, which requires high-temperature processing and is limited to fluorine-doped tin oxide (FTO) substrates. In this study, we report the fabrication of a fully ambient-air processed green-solvent based FAPbI₃ PSC on ITO substrates using a low-temperature double ETL structure. The architecture combines sputtered compact TiO₂ (c-TiO₂) with solution-processed SnO₂ nanoparticles, improving charge extraction and reducing shunt paths. The average open-circuit voltage improved from 0.959 ± 0.029 (V) in single-layer SnO₂ reference devices to 1.059 ± 0.003 (V) with the double ETL. The maximum PCE achieved was 19.92% (18.175± 1.216%) compared to 18.01% (15.589± 1.238%) for reference cells. Remarkably, the double ETL devices exhibited excellent stability, retaining 101.5% of their initial PCE after 432 hours of shelf storage, while the PCE of the reference devices declined to 92% over the same duration. Preliminary results on fully sputtered double ETL will also be shown. In conclusion, this work offers a scalable, air-processed route to stable and high-performance PSCs.

References:

[1] Mali, Sawanta S., et al. "Efficient planar nip type heterojunction flexible perovskite solar cells with sputtered TiO 2 electron transporting layers." Nanoscale 9.9 (2017): 3095-3104.

[2] Qiu, Longbin, et al. "Scalable fabrication of stable high efficiency perovskite solar cells and modules utilizing room temperature sputtered SnO2 electron transport layer." Advanced Functional Materials 29.47 (2019): 1806779.

[3] Onyeagba, Chijioke Raphael, et al. "Investigating the properties of tin-oxide thin film developed by sputtering process for perovskite solar cells." Materials for Renewable and Sustainable Energy 12.1 (2023): 31-37.

[4] Hayali, Ahmed, and Maan M. Alkaisi. "High efficiency perovskite solar cells using DC sputtered compact TiO2 electron transport layer." EPJ Photovoltaics 12 (2021): 8.

[5] Alberti, Alessandra, et al. "Nanostructured TiO2 grown by low-temperature reactive sputtering for planar perovskite solar cells." ACS Applied Energy Materials 2.9 (2019): 6218-6229.

[6] Kam, Matthew, et al. "Room-temperature sputtered SnO2 as robust electron transport layer for air-stable and efficient perovskite solar cells on rigid and flexible substrates." Scientific reports 9.1 (2019): 6963.

Acknowledgements:

This project has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement no. 101122283. (PEARL)

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