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 (T-2), in perovskite films to improve the performance and stability of planar perovskite solar cells (PSCs). The results indicate two major functions of T-2 in PSCs: improving the perovskite crystal quality due to the interaction between T-2 and perovskite and eliminating Pb-0 and I-0 defects by redox reaction, allowing for the regeneration of T-2 in the process. We achieved a power conversion efficiency (PCE) of PSCs with T-2 of 20.67%, a 15% increase compared to the control device (17.9%). Furthermore, PSC devices with T-2 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 degrees C, 40% humidity) for 2 months.