Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV23)
Publication date: 30th March 2023
Perovskite polycrystalline films exhibit numerous intrinsic and interfacial defects that can be attributed to the solution preparation process. These defects adversely affect both the photovoltaic performance and the reliability of perovskite solar cells (PSCs). In this study, we have systematically investigated the use of 1,3,7-trimethylxanthine (C8H11N4O2), commonly known as caffeine, as an additive for improving the quality of triple cation engineered perovskite films. The addition of caffeine to perovskite films induced a preferred crystal orientation through coordination interactions between the carbonyl (C=O) groups of caffeine and Pb2+ ions in perovskite. The caffeine-added device was found to promote crystal growth, resulting in simultaneous improvement of both power conversion efficiency (PCE) and stability of PSCs. When 0.75 wt% of caffeine additive was added, a maximum PCE of 21.07% was obtained and the device exhibited improved stability, maintaining over 85% of its initial PCE after 1000 hours under ambient air conditions.
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (NRF-2021R1A4A1031920) and the Ministry of Education (NRF-2022R1I1A1A01053885).