Stability Improvement of Perovskite Solar Cells for Application of CuInS2 Quantum Dot-Modified TiO2 Nanoarrays

In this work, we developed a CH3NH3PbI3 perovskite solar cell with CuInS2 quantum dot-modified TiO2 nanoarrays (TiO2–CuInS2 QD-NAs) as a scaffold layer. Based on the suitable device configuration, we achieved improved power conversion efficiency (PCE) of 13.3%, which was 38.3% higher than that of the device without QD modification (8.2%). After exposure to air for 30 days, the TiO2–CuInS2 QD-NA-based device possessed a PCE of 5.4%, being 41% of the original performance, which was far superior to that of TiO2 nanoarray-based solar cells with a PCE of 1.1%. Our results showed that the crystallinity of perovskite, surface state, and interface for charge transport of TiO2–CuInS2 QD-NA-based perovskites all remarkably improved, indicating the improved air stability for TiO2–CuInS2 QD-NA-based solar cells.