Fluorene-Terminated π-Conjugated Spiro-Type Hole Transport Materials for Perovskite Solar Cells
Mengde Zhai, Kaihuai Du, Chengyang Liu, Cheng Chen, Guixiang Li, Haoxin Wang, Ziyang Xia, Jinman Yang, Hui Xu, Aili Wang, Toshinori Matsushima, Zhanglin Guo, Meng Li, Antonio Abate, Paul J. Dyson, Mohammad Khaja Nazeeruddin, Ming Cheng
Abstract
High Resolution Image Download MS PowerPoint Slide Spiro-OMeTAD is a widely used hole transport material (HTM) in perovskite solar cells (PSCs), but its inherent low hole mobility and poor thermal stability affect the overall performance of PSCs. To overcome these limitations, we develop a series of fluorene-terminated Spiro-type HTMs, engineered by modulating the fluorene substitution site and π-conjugated intensity. Among these, the p -BM material exhibits high energetic ordering in film, appropriate energy levels, and efficient carrier extraction, enabling PSCs to achieve power conversion efficiencies (PCEs) of 25.5% and 24.03% for aperture areas of 0.0625 and 1 cm 2, respectively. Additionally, a perovskite solar mini-module (size 16 cm 2 ) based on p -BM HTM achieved a PCE of 22.4%. More importantly, p -BM exhibits a high glass transition temperature and enhanced film hydrophobicity, significantly improving the stability of devices in relation to heat and humidity. Our findings provide a promising alternative HTM for developing efficient and stable perovskite photovoltaic devices.