Preparation Of Silver Nanowires And Titanium Carbide Composite Transparent Electrode And Its Application In Photoelectric Detection

Silver nanowire（AgNWs）networks have the advantages of bending resistance,high electrical conductivity,and wide spectral transmittance,which are expected to replace commercial tin doped indium oxide as the next generation of transparent electrode materials,and have an important application prospect in liquid crystal display,touch screen,photodetector and other fields.However,the application of AgNWs networks is limited by its poor chemical stability,low efficiency of carrier collection and difficult adjustment of work function.Titanium carbide（Ti₃C₂T_x）,as a new two-dimensional lamellar material,has the characteristics of good electrical conductivity,abundant surface functional groups and adjustable work function.If Ti₃C₂T_x is coated on the surface of AgNWs to form a composite transparent electrode,it can not only improve the stability and carrier collection efficiency of AgNWs,but also achieve the purpose of regulating the work function of AgNWs,which is of great significance to improve the photoelectric performance of the transparent electrode of AgNWs and expand its application range.In this thesis,Ti₃C₂T_x-AgNWs composite transparent electrode was prepared by the method of spin-coating and electrophoresis deposition.The work function of the composite transparent electrode was adjusted by plasma treatment.The effect of composite transparent electrode on gallium oxide solar blind UV detector was studied.The main research contents are as follows:（1）Preparation and photoelectric properties of AgNWs-Ti₃C₂T_x composite transparent electrode.Firstly,the AgNWs network was prepared by spin coating method.Secondly,two-dimensional Ti₃C₂T_x nanosheets were selectively deposited on and near the surface of the AgNWs network by electrophoretic deposition technology.By controlling the density of AgNWs network and the thickness of Ti₃C₂T_x layer,and the photoelectric properties of the composite transparent electrode were optimized.The average transmittance of the AgNWs-Ti₃C₂T_x composite transparent electrode in the ultraviolet to visible region（200-800 nm）was higher than 80%,and the surface resistance was less than 20?/sq.（2）Regulation and mechanism of plasma treatment on the work function of AgNWs-Ti₃C₂T_x composite transparent electrode.The work function of composite transparent electrode materials treated with hydrogen and oxygen plasma was studied by atomic force microscopy（AFM）.The results showed the work function of the composite transparent electrode material decreased（increased）from 5.03 e V to 4.90（5.38）e V after the H₂（O₂）plasma treatment.Raman spectroscopy,infrared spectroscopy and X-ray photoelectron spectroscopy were used to investigate the microstructure changes of the composite transparent electrode before and after plasma treatment.It is proved that H₂（O₂）plasma treatment can increase the number of hydrogen（oxygen）terminating groups on the surface of Ti₃C₂T_x,and thus regulate its dipole moment and work function.（3）Application of AgNWs-Ti₃C₂T_x composite transparent electrode for photoelectric detection.A self-actuated solar-blind ultraviolet photoelectric detector was constructed by depositing AgNWs-Ti₃C₂T_x composite transparent electrode on Ga₂O₃/FTO substrate.The effects of Ti₃C₂T_x coating and work function on the optical response characteristics of the detector were studied.Compared with the detector with AgNWS transparent electrode,Ti₃C₂T_x-coated AgNWs transparent electrode can increase the device’s responsiveness to 254 nm light by 5 times to 5.3 m A/W,accelerate the recovery time of optical response by 40 times to 0.70 s,and significantly improve the cycling stability.In addition,the optical responsiveness of the device after oxygen plasma treatment is further increased,reaching 9.2 m A/W.Based on the energy band theory,the reason is that the oxygen plasma treatment increases the work function of AgNWs-Ti₃C₂T_x,which leads to the elevation of the Schottky barrier between the transparent electrode and Ga₂O₃.