Enhanced Photocatalytic Property of γ-CsPbI3 Perovskite Nanocrystals with WS2

Black perovskite-phase cesium lead tri-iodide (CsPbI 3 ) has shown great potential in photochemical applications. However, colloidal CsPbI 3 still suffers from the existence of ligands attached to the surface of nanocrystals (NCs) and serious photoluminescence (PL) quenching. Here, we develop two different γ-phase CsPbI 3 (γ-CsPbI 3 ) NCs/WS 2 heterostructures with two different two-dimensional morphologies of WS 2 (nanoplates and few-layered WS 2 nanosheets) to improve the photocatalytic property of γ-CsPbI 3 NCs. The large surface area and the presence of abundant functional groups on the surface of WS 2 enable a bonding interaction with precursors in the mixture solution, which can reduce the number of ligands and promote the formation and crystal quality of γ-CsPbI 3 NCs. Exhilaratingly, we find that γ-CsPbI 3 NCs fabricated with few-layered WS 2 nanosheets exhibit a significant enhancement in their photocatalytic property, which may result from the increased amount and improved crystal quality of γ-CsPbI 3 NCs and the superior carrier-transport property of few-layered WS 2 nanosheets, and these effects are beneficial for producing abundant hydroxyl radicals to completely degrade methylene blue (MB). The fresh γ-CsPbI 3 NCs/few-layered WS 2 nanosheets show a high photocatalytic degradation efficiency of nearly 100% in 30 min, and completely degrade MB into low-weight and low-toxicity inorganic molecules without any intermediate degradation products.