Metal Halide Perovskite/Chalcohalide Heterojunctions for the Photoinduced Oxidative Coupling of p‑Substituted Thiophenols

The introduction of a semiconductor–semiconductor junction is an effective strategy to enhance the photocatalytic performance of perovskite nanocrystal-based systems. Herein, we optimized the synthesis of CsPbX3/Pb4S3Y2 (X, Y = Cl, Br, I) perovskite/chalcohalide heterostructures, whose band alignment can be tuned by the halide composition. As a proof-of-concept, we evaluated the photooxidative coupling of p-substituted thiophenols at room temperature, under visible light, in air, and without a sacrificial electron donor. Notably, CsPbBr3/Pb4S3Br2 achieved up to 94% selectivity toward disulfide (p-OCH3 thiophenol with a turnover number of 14 300), highlighting the crucial role of the type-II heterojunction in promoting charge separation and efficient electron delocalization across the junction.