Bifunctional Organic Disulfide for High-Efficiency and High-Stability Planar Perovskite Solar Cells

In this study, we used a bifunctional organic disulfide, di-5-(1-methyltetrazole) disulfide (T2), in perovskite films to improve the performance and stability of planar perovskite solar cells (PSCs). The results indicate two major functions of T2 in PSCs: improving the perovskite crystal quality due to the interaction between T2 and perovskite and eliminating Pb0 and I0 defects by redox reaction, allowing for the regeneration of T2 in the process. We achieved a power conversion efficiency (PCE) of PSCs with T2 of 20.67%, a 15% increase compared to the control device (17.9%). Furthermore, PSC devices with T2 exhibited enhanced operational stability and storage stability. During 140 s of operation, there was no evident decrease of PCE. The device maintained 95% of its initial efficiency without encapsulation under ambient conditions (20 °C, 40% humidity) for 2 months.