| Photodetectors are electronic devices that convert optical signals into other signals,and are widely used in health monitoring,medical imaging,memory resistance,nanobots,astronomical detection and other fields.With the application expansion of flexible electronics and wearable electronic devices,people have put forward higher requirements for the multi-function,flexibility and biocompatibility of photodetectors.The flexibility of the photodetector is achieved by substrate modification,functional layer optimization,and device structure layout.Conventional flexible photodetectors are mainly based on two-dimensional polymer films,metal foil or fibrous paper,and are difficult to integrate or be woven into clothing,limiting their use in wearable devices.Because of their excellent flexibility,weaving and comfort,fiber materials can help to"wear"wearable electronics.However,the flexible process of photodetector leads to the power supply of the device,which makes the contradiction between performance and power consumption more prominent.Exploring the new energy supply mode of photodetectors and forming the self-powered system of continuous power supply has become the research hotspot and frontier of related fields.In this paper,self-powered photoelectric sensor is constructed based on Zn O nanorod array,which realizes high linearity self-powered ultraviolet light position detection by using defect structure and photothermoelectric cooperative gain mechanism,realizes micro electric field modulation of fiber-shaped Zn O/P3HT photodetector with piezoelectric optoelectronics gain,and realizes self-powered,ultrafast and high sensitivity response of alginate fiber-shaped Zn O/MAPb X3/P3HT double heterojunction photodetector by using chlorobenzene molecular processing technology.The specific research contents are as follows:（1）In the defection-rich Zn O nanorods array,the thermal photoelectron synergistic effect is utilized to regulate the heat conduction and electron transport,and the photoelectric energy conversion and self-powered position-sensitive light detection are significantly improved.The thermoelectric and photothermal properties of transverse Zn O nanorods arrays have been studied by growing dense Zn O nanorods arrays on the surface of planar rigid substrates by cryogenic hydrothermal synthesis method,and they have been used for position-sensitive photoelectric detection.At the same time,intrinsic defects were introduced into Zn O nanorods to study the photothermoelectron effect of defect triggering in Zn O nanorods arrays with abundant lattice defects.The results show that the output signal of the Zn O nanorods array has a linear relationship with the illumination position,and the position sensitivity is 0.19 m V·mm-1 at room temperature.At the same temperature difference between the two ends of the device,the thermoelectric signal of Zn O nanoarray is higher than that of photothermal signal.The thermoelectric and photothermal coupling can compensate for the inhibition of photothermal power generation.At the same time,the defected Zn O devices have high conductivity and large Seebeck coefficient,which can significantly improve the photoelectric conversion and self-powered photoelectric detection.The synergistic effect of the intrinsic defects and the applied temperature field can promote the photothermoelectric properties of the compact Zn O nanorods array.（2）Based on the metal fiber which can be used as both electrode material and substrate material,a fiber-shaped photodetector composed of vertical organic-inorganic heterostructure was constructed.Under the control of coaxial heterojunction and piezoelectric photoelectron effect,self-powered light detection and improved photoelectric response were realized.The neat and uniform Zn O nanorods were grown on the surface of the metal fibers by low temperature hydrothermal synthesis method,and formed a vertical coaxial p-n junction with P3HT on the surface of the fibers.Flexible metal wires and conductive alginate fibers were used as internal and external electrodes.A novel fiber-shaped photodetector based on a coaxial p-n junction supported by metal fibers can realize self-powered response to UV light without any bias,and the response and recovery time is very short（<40 ms）.By controlling the bending induced piezoelectric potential of the photodetector,when the strain is 1.96%,the piezoelectric photoelectron effect improves the light response of the device by 81.2%compared with that without strain.The finite element simulation shows that the nonuniform strain and the distribution of piezoelectric potential on the bent metal fiber device promote the separation of the interfacial carriers of coaxial p-n junction,thus improving the optical detection ability.（3）Combined with the flexibility of alginate fiber,semiconductor characteristics of Zn O and excellent photoelectric performance of organic-inorganic hybrid perovskite quantum dots（MAPb X3 QDs）,a novel alginate fiber-based double heterojunction self-powered photodetector was prepared.By studying different hydrothermal synthesis conditions,the optimum method of Zn O nanorods arrays on alginate fiber surface was explored.Under the action of 1,2-dichlorobenzene,MAPb X3 QDs crystallizes and forms a film on the surface of Zn O nanorods,and forms a heterogeneous structure with Zn O.By comparing the self-powered response of fiber photodetectors based on different heterojunctions to UV light,it can be found that compared with single heterojunctions,double heterojunctions can effectively improve the optical detection capability of the devices.At the same time,the Zn O/MAPb X3 Film/P3HT double heterojunction can greatly improve the photoelectric response of the device.The Ag/Zn O/MAPb X3 Film/P3HT/PEDOT:PSS/Ag photodetector based on alginate fiber can not only realize self-powered optical detection of UV light,but also achieve high detectivity（3.1×109 Jones）and achieve rapid response and recovery（response/recovery time<40 ms）. |
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