| Because deep ultraviolet light will be absorbed by the ozone layer,the photoelectric detection in this band will not be affected by sunlight,so it is also called sun-blind ultraviolet.Its natural low background noise and other advantages make it have a bright future in remote monitoring,fire monitoring,engine tail flame tracking,remote communication and other aspects.Perovskite self-powered photodetectors are widely used in near-ultraviolet and visible band detection due to their excellent optical properties,such as high absorption coefficient and fast response speed,low dark current,and can be prepared by solution method,and can work without applied bias.However,due to the strong absorption of deep ultraviolet by the transmission layer,the detection in deep ultraviolet band is difficult to apply.Perovskite quantum dots have the advantages of high quantum efficiency and easy preparation,which can efficiently convert deep ultraviolet light into visible light.Therefore,in this paper,perovskite quantum dots are used as deep UV conversion layer to solve the problem of low response of self-powered perovskite photodetectors to deep UV light.The following work has been carried out.（1）MAPbBr3quantum dots/PVDF thin films were prepared in situ by DMF-assisted stepwise annealing.The process was simple and there was no waste liquid.The product composition was characterized by XRD,UV and PL spectra.By characterizing the products at different reaction stages,it was confirmed that the reaction was carried out in two steps.Firstly,PVDF skeleton is formed during annealing in DMF atmosphere.In the second step,DMF between PVDF skeletons continues to volatilize,and perovskite and unfixed PVDF continue to crystallize to form a cladding structure.（2）We treated the perovskite/PVDF precursor solution with ultrasound,and found that ultrasound would affect the crystallinity of PVDF films.By characterizing the crystallization process of the film,we found that the crystallinity of PVDF has a limited effect on the growth of perovskite.By controlling the ultrasonic time,we can control the size of perovskite quantum dots,and obtain a fairly stable perovskite quantum dots/PVDF film,which still has obvious fluorescence after 300 days in the air environment.（3）We use MAPbBr3quantum dots/PVDF film as the down-conversion layer of the deep ultraviolet photodetector.The device shows excellent responsiveness and repeatability,and shows 0.14A/W high responsiveness and 1.49×1012Jones detection for 275 nm deep ultraviolet light without applied bias.At the same time,we have achieved the resolution of deep ultraviolet and visible light on the same device through parallel structure design. |
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