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

Abstract

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 (V₂O_x) aqueous solution is mixed with a CH₃NH₃PbI_3−xCl_x precursor solution, resulting in an improvement in the CH₃NH₃PbI_3−xCl_x film. Perovskite films with large crystal sizes could be obtained using V₂O_x 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 V₂O_x additives in ambient air. It is via a physical mechanism that V₂O_x particles are dispersed in the perovskite crystal boundary, and the heterogeneous structure between CH₃NH₃PbI_3−xCl_x and V₂O_x 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 CH₃NH₃PbI_xCl_3−x:V₂O_x (2.5 wt%) still maintain a high PCE after being stored for 1000 h, more than 70% of the initial one.