Preparation And Photoelectric Properties Of CsPbBr₃/Al₂O₃ Heterojunctio

The heterojunctions formed by all-inorganic perovskite quantum dots and metal oxide semiconductors have been widely used in optoelectronic devices.Compared with conventional metal semiconductor oxides,porous Al₂O₃ with nanometer size had wider band gap and more stable physical and chemical properties,and it was easy to achieve energy level collimation with other materials,thus improving carrier transport efficiency.In this paper,colloidal CsPbBr₃ quantum dots（QDs）and nano-porous Al₂O₃were used to construct semiconductor heterojunction,The main research contents were as follows:（1）The CsPbBr₃ QDs were prepared by the thermal injection method.The results showed that CsPbBr₃ QDs showed strong photoluminescence（PL）,the PL emission and absorption peaks were located at 513 nm and 496 nm,and the fluorescence half peak width was 21 nm.In addition,the synthesized CsPbBr₃ QDs presented a cubic crystal structure.（2）The CsPbBr₃/Al₂O₃ and CsPbBr₃/Au/Al₂O₃ heterojunctions were prepared respectively.The results show that CsPbBr₃ QDs clusters can be observed on the surface of porous Al₂O₃ and Au@Al₂O₃.The peak positions of porous Al₂O₃and CsPbBr₃ can be simultaneously observed by PL and UV-Vis spectra.The quenching of CsPbBr₃QDs on the Al₂O₃ surface decreased CsPbBr₃/Al₂O₃ heterojunction PL.Owing to the introduction of Au nanoparticles,there was an effective resonance coupling between the local surface plasmon resonance effect of Au nanoparticles and the excitons in CsPbBr₃,which enhanced the PL and UV-Vis of CsPbBr₃/Au/Al₂O₃ heterojunction.（3）A photoconductivity detector and a vertical photodetector was prepared in this paper.The results showed that the best time of sputtering Au nanoparticles was 30s in the photoconductivity type detector.Under the ultraviolet light of 365 nm,the on/off ratio of 30s@Au CsPbBr₃/Au/Al₂O₃ photodetector was increased by 6 times compared with CsPbBr₃/Al₂O₃ photodetector.The responsivity of the modified CsPbBr₃/Au/Al₂O₃ photodetector was increased from 0.122 A/W to 0.424 A/W.With the increase of the illumination power,the light response of vertical photodetectors was increased,and can be self-powered without an external power supply.