Hybrid organic-inorganic perovskite solar cells (PSCs ) have shown promise for the next generation of photovoltaics. Pusan National University Joonkyung Jang, Min-cheol Kim and UC San Diego David P. Fenning et al. proposed a simple method to enhance the common hole transport material (HTM ) Spiro-MeOTAD by replacing the central carbon atom with a silicon atom. PSC performance and stability. This modification, called Si-Spiro, increases hole mobility. Density functional theory simulations indicate that the enhancement in hole mobility is due to structural changes in Si-Spiro. Electron beam induced current microscopy measurements demonstrate improved charge extraction at the Si-Spiro/perovskite interface.
The Si-Spiro-based PSC achieves a power conversion efficiency of 22.5%, which is better than the standard Spiro-MeOTAD . Furthermore, Si-Spiro-based PSCs exhibited enhanced stability, maintaining over 90% performance over 120 hours of operation. Depth profiling X-ray photoelectron spectroscopy shows that Si-Spiro can effectively prevent metal ion migration, thus improving its stability. The research results show that Si-Spiro is expected to become a high-performance and stable HTM for PSCs.
Yanqi Luo, Ramesh Kumar Chitumalla, So-Yeon Ham, Deniz N. Cakan, Taewoo Kim, Sanghyun Paek, Ying Shirley Meng, Joonkyung Jang*, David P. Fenning*, and Min-cheol Kim*, A Si-Substituted Spirobifluorene Hole-Transporting Material for Perovskite Solar Cells, ACS Energy Lett. 2023, 8, 5003–5011