Exploring a Novel Family of Conjugated Polymers for High Efficiency and Thermally Stable Perovskite Solar Cells

Long-term stability remains to be one of the critical challenges for organic-inorganic hybrid perovskite solar cells (PSCs). One of the most important limiting factors toward achieving long-term stability has been attributed to the hole transport layer (HTL), originating from interfacial degradation between perovskite and HTL, thermal/moisture induced degradation, and ionic migration. In this work, we examine novel conjugated polymer (CP)-based HTLs that are resistant to high temperatures in PSCs. CPs offer efficient hole extraction/transport properties, easy processing, and low-production cost. We highlight differences in optoelectronic properties, crystallinity, and stability of the CPs with respect to its different chemical structures using measurements including UV-VIS, UPS, DSC, GIWAXS, and XPS. These new polymers are further incorporated into devices to analyze its photovoltaic performance and stability at elevated temperature under illumination over 200 hours.