Metal Halide Perovskite/Chalcohalide Heterojunctions for the Photoinduced Oxidative Coupling of <i>p</i> -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 <i>p</i>-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 (<i>p</i>-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.