Construction Of Flexible UV Photodetector Based On ZnO By All-Solution Strategy And Performance Study

Flexible and wearable photodectors?PDs?have recently attracted extensive attentions due to their wide applications in communication,health and safety.Ultraviolet detector is widely used in civil and military fields because of its strong anti-interference ability and high detection sensitivity.However,the reported fiber-and textile-shaped PDs with the problem of low mechanical strength and weak interface contact are difficult to realize the wearable applications.Hence,we developed a kind of wearable PDs with ultra-flexible property,high mechanical strength and excellent optical and electrical properties using full-solution method which is compatible with industrial mass production.In this work,the ultra-flexible PVDF?Polyvinylidene Fluoride?porous filter membrane was used as the flexible substrate to construct the flexible ultraviolet detector.Here,a kind of quasi-paper flexible UV photodetectors?PDs?based on Polyvinylidene Fluoride?PVDF?filter membrane with the structure of Ag nanowires/ZnO nanowires/graphene were fabricated by full-solution method.ZnO nanowires with high crystalline were prepared by chemical vapor deposition.The diameter of ZnO nanowires approximately were 50nm and thickness of the film was 3.5?m.The device construction method of vacuum filtration confirms the close contact between functional layers.Graphene monolayer continuous thin film with high quality used as the transparent electrode promoted stable and fast transfer of the carriers inside the device.The full-solution method has the advantages of simple assembling,low cost and compatibility with industrial mass production.The flexible ultraviolet photodetectors based on ZnO constructed in the experiment have outstanding excellent device performance and flexibility.The photo response band of the PDs is 300-380nm.The built-in electric filed due to Schottky junction of the ZnO/graphene is in favor of the separation and transportation of photo-generated carriers,leading to excellent device performance.The rise and fall time of the device were 7.31s and 5.24s.The I_light/I_darkark ratio was as high as 10².The PDs with remarkable flexibility can be easily attached to the human bodies and even can work steadily under serious bending conditions,especially the photocurrent kept 95%of the maximum value after the PDs bent for 1000 times.CsPbBr₃ NSs layer was introduced between ZnO layer and graphene electrode layer by the concern of interface engineering to optimize the device performance.Then,we proposed a simple solution strategy to construct flexible PDs based on PVDF substrate with the structure of ZnO NWs/CsPbBr₃ NSs/graphene.The CsPbBr₃ NSs smoothed the contact interface between ZnO and graphene,and the high light absorption coefficient promoted the light absorption of the device.The built-in electric field due to pn junction of ZnO/CsPbBr₃ is in favor of the separation and transportation of the photo-generated carriers.Evidently,the rise and fall time of the device were 4.50s and 4.82s,the I_ligtht/I_dark ratio was as high as 10³,and superior to the former PDs by one order of magnitude.Additionally,the detector array based on the full-solution method can be applied to wide range of optical detection and realize the application of sensing imaging.