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.