An improvement in un-Encapsulated perovskite solar cell’s environmental stability via introduction of an electrode interface layer

Perovskite solar cells (PSCs) have shown power conversion efficiency (PCE) up to 25.5%, but they are still struggling with their poor environmental stability. We have improved the ecological stability of un-encapsulated PSCs via interface modification of the top metal electrode. We used CH3NH3PbI3-xClx perovskite as the light absorber and Ag metal as the top electrode. The interface of Ag electrode was modified by introducing a thin layer of MoOx/Al before Ag. We observed that MoOx/Al interlayer before Ag imparts better stability to the devices than conventional Ag electrode only. We found that MoOx/Al interlayer impedes the diffusion of oxygen and metal electrode into the perovskite film and considerably halts the device degradation upon being kept for about 350 h under laboratory ambient conditions (room temperature 25±2oC and humidity 40±5%). This work mainly highlights the role of interfaces in PSCs degradation, and will help to address the stability issues in PSCs.