Research On Performance Optimization And Optical Communication System Integration Of Low-Dimensional ZnO Self-Powered Photodetector

Optical communication with the charm of high bandwidth opens up a brandnew space for wireless communication technology.Among them,ultraviolet（UV）communication is highly appealing owing to its inherent advantages of non-line-ofsight communication and anti-interference,and photodetectors as optical receivers is a key component for achieving accurate information transmission.Currently,commercial photomultiplier tubes and avalanche photodiodes are still the main photodetectors in UV communication systems.However,their high applied voltage,complicated preparation process and high cost limit the development of UV communication systems toward portability and flexibility.Self-powered photodetectors without external power supply as optical receivers offer great opportunities for UV communication technology,and it is of great significance to develop high-performance self-powered UV photodetectors to satisfy efficient UV communication applications.In this article,guided by the optical communication application of self-powered photodetector,a series of research work focusing on the performance optimization of low-dimensional ZnO self-powered UV photodetectors is carried out.The local surface plasmon resonance（LSPR）,photothermal effect and interface engineering are introduced on the basis of pyrophototronic effect,which significantly improves the performance of self-powered UV photodetectors without external field assistance.The underlying mechanism of various optimization strategies on the carrier behaviors is systematically and deeply analyzed.On this basis,an UV communication system with high transmission rate is designed and integrated by using the low-dimensional ZnO self-powered photodetector as the optical receiver.The growth of ZnO nanowires（NWs）is controlled,the self-powered Ag NPs@ZnO NWs/PEDOT:PSS heterojunction UV photodetector is designed and constructed,and the optimization strategy of introducing LSPR to enhance the pyro-phototronic effect is developed.The self-powered Ag NPs@ZnO NWs/PEDOT:PSS UV photodetector exhibits a maximum responsivity of 25.4 mA W-1,a specific detectivity limit of 6.73×1010 Jones,and a fast response time of 0.1 ms.It is revealed that the LSPR enhances the incident light absorption of ZnO NWs,plasmonic heat effect improves the pyroelectric effect of ZnO NWs,and local Schottky barrier works together,which achieves the simultaneous improvement of UV light utilization and carrier separation efficiency,thus significantly optimizing the performance of the self-powered photodetector.Ti₃C₂T_x nanosheets is prepared by control,and Ti₃C₂T_x@PEDOT:PSS nanocomposite is synthesized.The self-powered ZnO/Ti₃C₂T_x@PEDOT:PSS heterojunction UV photodetector is designed and constructed,where the Ti₃C₂T_x with excellent conductivity and photothermal conversion efficiency is used to enhance the pyro-phototronic effect.The self-powered ZnO/Ti₃C₂T_x@PEDOT:PSS UV photodetector exhibits superior comprehensive performance with a maximum photoresponsivity of 12.3 mA W-1,a specific detectivity limit of 1.47×1011 Jones,a fast response time of 62.2 μs and excellent switching cycle stability.It is clear that the enhancement of photothermal conversion,the improvement of PEDOT:PSS conductivity and the increase of the built-in electric field effectively promote the separation and transmission of photogenerated carriers and inhibit their recombination.By using Ti₃C₂T_x nanosheets as interface modification layer,the self-powered ZnO/Ti₃C₂T_x/PEDOT:PSS heterojunction UV photodetector is designed and constructed.An optimization strategy of introducing interface engineering on the basis of the pyro-phototronic effect is proposed.The self-powered ZnO/Ti₃C₂T_x/PEDOT:PSS photodetector exhibits a maximum responsivity of 17.1 mA W-1,a limited specific detectivity of 6.76×1011 Jones and a rapid response time of 30.9 μs.It is revealed that the barrier height between Ti₃C₂T_x and ZnO can effectively increase the built-in electric field of heterojunction,and the modification of Ti₃C₂T_x can effectively passivate the surface defect state of ZnO and combine with the pyro-phototronic effect to obtain a self-powered photodetector with superior performance.An UV communication system is designed and integrated based on the construction and performance optimization of low-dimensional ZnO self-powered photodetectors.The demonstration system realizes real-time high-throughput and accurate transmission of text at 9600 Baud rate.It is proved that the lowdimensional ZnO self-powered photodetectors as optical receivers in UV communication system are feasible and effective,achieving efficient information transmission,which lays a foundation for the further development and application of self-powered UV photodetectors.