All solution processed perovskite solar cells with Ag@Au nanowires as top electrode

In this paper, solution-processed Au-coated Ag nanowires (Ag@Au NWs) was successfully fabricated as top electrode by spray deposition in planar perovskite solar cells (PVSCs) with structure ITO/PTAA:F4-TCNQ/MAPbI3/PC61BM/Ag@Au NWs, which shows favorable bandgap alignment. Sheet resistance of electrode and series resistance of solar cells over time as well as the stability of PVSCs were measured. The results indicate that the Au shell which serves as a physical separation layer sandwiched in between the perovskite/hole transporting layer (HTL) and the halide-reactive silver nanowires (Ag NWs) can significantly enhance the stability of PVSCs. The efficiency of solar cells employing Ag NWs as top electrode decreases rapidly within 10 min while the efficiency of solar cells employing Ag@Au NWs still remains 85% of its original efficiency even after one week in air. The as-fabricated PVSCs exhibit a power conversion efficiency of 11.0% with an open-circuit voltage of 0.99 V, a short-circuit current density of 18.5 mA/cm2, and a fill factor of 64.3%. This work paves a way for realizing low cost, stable, all solution processable PVSCs.