Publication
Engineering of inorg.-org. lead halide perovskites for photovoltaic applications has experienced significant advances in recent years. However, the use of the relatively expensive spiro-OMeTAD as a hole-transporting material (HTM) poses a challenge due to dopant-induced degrdn. Herein we introduce two new three-armed and four-armed HTMs (BTT-4 and BTT-5) based on isomeric forms of benzotrithiophene (BTT). The isomerism impact on the optical, electrochem. and photophys. properties and the photovoltaic performance is systematically investigated. Perovskite solar cells (PSCs) using BTT-4 and BTT-5 as HTMs show remarkable light-to-energy conversion efficiencies of 19.0% and 18.2%, resp., under std. measurement conditions. These results validate the readily available BTT heteroarom. structure as a valuable core for the design of highly efficient HTMs for the prepn. of PSCs.
Philippe Schwaller, Junwu Chen
Mohammad Khaja Nazeeruddin, Peng Gao, Paramaguru Ganesan