Affiliation:
1. Key Laboratory for Optoelectronic Information Perception and Instrumentation of Jiangxi Province Nanchang Hangkong University Nanchang 330063 P. R. China
2. National Engineering Laboratory for Non‐Destructive Testing and Optoelectronic Sensing Technology and Applications Key Laboratory of Nondestructive Testing Ministry of Education School of the Testing and Photoelectric Engineering Nanchang Hangkong University Nanchang 330063 P. R. China
Abstract
AbstractCesium lead triiodide (CsPbI3) perovskites have garnered significant attention owing to their suitable bandgap for tandem silicon substrates and excellent chemical stability. However, γ‐CsPbI3 prepared via low‐temperature co‐evaporation is limited by a narrow black phase processing window and random crystal orientation, hindering its optoelectronic performance and industrial applications. This study introduced trace amounts of methylammonium iodide (MAI) into the co‐evaporation system, enhancing the crystallization process, promoting columnar grain growth, and stabilizing the γ‐phase perovskite, resulting in films with improved structural integrity and reduced defect density. The optimal Pb/Cs ratio for achieving the best photoelectric performance shifted from 1:1 to 1.1:1 in the presence of MAI. Additionally, the incorporation of MAI allowed for more efficient longitudinal carrier transport, as evidenced by the enhanced photoluminescence (PL) intensity. The bandgap of CsPbI3 remained approximately at 1.7 eV before the δ‐phase transition, ensuring suitability for photovoltaic applications. Ultimately, a photovoltaic device with 12% efficiency is achieved in the p‐i‐n structure without additional post‐annealing of the CsPbI3 perovskite films, demonstrating the practical benefits of MAI incorporation.
Funder
National Natural Science Foundation of China