Efficient and stable perovskite solar cells based on high-quality CH3NH3PbI3-xClx films modified by V2Ox additives

The method of preparing perovskite films in ambient air is of great importance to commercializing high-performance planar perovskite solar cells (PSCs). Herein, an efficient and stable inverted planar PSC has been prepared via a simple solution method in ambient air. A suitable vanadium oxide (V2Ox) aqueous solution is mixed with a CH3NH3PbI3-xClx precursor solution, resulting in an improvement in the CH3NH3PbI3-xClx film. Perovskite films with large crystal sizes could be obtained using V2Ox additives. The improvement in the performance of perovskite films is conducive to the separation and transmission of charge carriers. For PSCs, the highest power conversion efficiency (PCE) of 16.14% was obtained by controlling the proportion of V2Ox additives in ambient air. It is via a physical mechanism that V2Ox particles are dispersed in the perovskite crystal boundary, and the heterogeneous structure between CH3NH3PbI3-xClx and V2Ox is formed. In addition, the slow migration of iodide ions and stability of the perovskite films are also achieved. What merits more attention is that the PSCs with CH3NH3PbIxCl3-x:V2Ox (2.5 wt%) still maintain a high PCE after being stored for 1000 h, more than 70% of the initial one.