Silolothiophene-linked triphenylamines as stable hole transporting materials for high efficiency perovskite solar cells

In this work, we synthesized novel hole transporting materials (HTMs) and studied their impact on the stability of perovskite-based solar cells (PSCs). The steady-state maximum power output of devices in working condition was monitored to assess the stability and predict the lifetime of PSCs prepared using different HTMs. We showed that the HTM has a significant impact on the device lifetime and found that novel silolothiophene linked methoxy triphenylamines (Si-OMeTPAs) enable more stable PSCs. We reported Si-OMeTPA based devices with a half-life of 6 K h, compared to 1 K h collected for the state-of-the-art PSCs using spirofluorene linked methoxy triphenylamines (spiro-OMeTADs) as HTMs. We demonstrated that such a clear improvement is correlated to the superior thermal stability of silolothiophene compared to the spirofluorene linked triphenylamine HTMs.