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

Herein, Sn4+‐doped copper (I) iodide (CuI) is prepared via a facile, cost‐efficient solution process, and the properties of Sn4+‐doped CuI, including morphology, crystalline phase, as well as optical and electrical properties, are investigated by varying the Sn4+ concentration. And by constructing transparent Sn4+‐CuI/ZnO hybrid UV photodetectors, the potential of Sn4+‐CuI as a p‐type material for high‐performance photodetection is investigated. It is found that Sn4+ doping has great effect on the morphology as the formation of Sn4+‐CuI thin sheets is observed, and the resistivity of Sn4+‐CuI could be tuned by controlling Sn4+ addition. The Sn4+‐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 Sn4+‐CuI/ZnO hybrid photodetectors mainly arises from the formation of type‐II p‐Sn4+‐CuI/n‐ZnO heterojunctions, and the better interface contact leads to higher carrier separation efficiency due to the existence of Sn4+‐CuI thin sheets. And the improved performance is also related to the optimized resistivity of Sn4+‐CuI. This study sheds light on the potential of doped CuI toward transparent, high‐performance photodetectors in the future.