High performance hybrid MXene nanosheet/CsPbBr3 quantum dot photodetectors with an excellent stability

All-inorganic CsPbBr3 perovskite quantum dots (QDs) are considered as a new generation of photoelectric material for the implementations in photodetection owing to their remarkable optoelectronic properties and optimized stability. However, the combination of the abundant trap states and unfavorable carrier transportation poses a critical hurdle for the fabrication of high- performance photodetectors. In this study, a facile strategy to significantly enhance the performance of CsPbBr3 QD photodetectors via evenly blending 2D Ti3C2TX nanosheets is systematically demonstrated. The uniformly distributed Ti3C2TX nanosheets successfully confine incident fugacious photons throughout CsPbBr3 QD thin films as a result of the spontaneously intensified surface electromagnetic fields, and the transportation of photogenerated carriers from CsPbBr3 QDs are simultaneously accelerated due to the high conductivity and well-matched work function of the nanosheets. Meanwhile, the hot electrons excited from the nanosheets can also partially contribute to the increase in photocurrent, and thereby the performance of the device sensitively develops as a function of the concentration of the nanosheets. Correspondingly, a 300% enhancement is equally observed with external quantum efficiency and responsivity of the CsPbBr3 QD/MXene nanosheet photodetectors in comparison with the pristine one under 490 nm light illumination for a long period of 4 months in the atmospheric environment.