Solution-Processed Transparent Sn4+-Doped CuI Hybrid Photodetectors with Enhanced Performances

Herein, Sn 4+ -doped copper (I) iodide (CuI) is prepared via a facile, cost-efficient solution process, and the properties of Sn 4+ -doped CuI, including morphology, crystalline phase, as well as optical and electrical properties, are investigated by varying the Sn 4+ concentration. And by constructing transparent Sn 4+ -CuI/ZnO hybrid UV photodetectors, the potential of Sn 4+ -CuI as a p-type material for high-performance photodetection is investigated. It is found that Sn 4+ doping has great effect on the morphology as the formation of Sn 4+ -CuI thin sheets is observed, and the resistivity of Sn 4+ -CuI could be tuned by controlling Sn 4+ addition. The Sn 4+ -CuI/ZnO hybrid photodetectors exhibit obviously enhanced photodetecting performance outperforming ZnO film and CuI/ZnO photodetectors by the same preparation method, including significantly improved on/off ratio, spectral responsivity, and shortened responsive time. The enhanced performance of Sn 4+ -CuI/ZnO hybrid photodetectors mainly arises from the formation of type-II p-Sn 4+ -CuI/n-ZnO heterojunctions, and the better interface contact leads to higher carrier separation efficiency due to the existence of Sn 4+ -CuI thin sheets. And the improved performance is also related to the optimized resistivity of Sn 4+ -CuI. This study sheds light on the potential of doped CuI toward transparent, high-performance photodetectors in the future.