Polymer Additives for Morphology Control in High-Performance Lead-Reduced Perovskite Solar Cells

摘要

The organic–inorganic halide perovskite solar cells (PSCs) are rapidly developed in just a few years due to its high power conversion efficiency. However, it still faces some critical issues, one of which is the presence of toxic lead (Pb~(2+)). Recent researches show that barium (Ba~(2+)) can partially replace the Pb2þ in perovskite structure and achieve a promising device performance because of its adequate ionic radius. However, the optimal replacement amount of Ba~(2+) in perovskite is still limited. Herein, the methylammonium (MA)/formamidinium (FA) mixed-cation perovskite is used as the active layer in PSCs and Pb~(2+) is partially substituted with Ba~(2+). Compared with the pure MA system, the best device efficiency can be achieved using higher Ba~(2+) replacement ratio. In addition, while introducing the appropriate polymer additive, the replacement ratio can be further increased without compromise of device efficiency. Using polyethylene glycol as polymer additive, 10.0 mol%Ba-doped MA/FA mixed-cation PSC with an efficiency of 16.1% can be realized. It is believed that this report provides an effective strategy to fabricate high-performance lead-reduced PSCs.