Construction And Properties Of Flexible Composite Transparent Electrodes Based On Metal Nanowires

Transparent electrodes?TEs?are a key component of optoelectronic devices,which are widely used in information display,solid-state lighting,and photoelectric conversion and so on.With the development of flexible electronics,wearable electronics,and portable electronic technology,higher requirements have been placed on transparent electrodes.Not only do they require excellent photoelectric performance,superior chemical stability,they also require high flexibility,low cost and large-area fabrication.At present,Indium tin oxide?ITO?has the most widespread use for TEs,but it is fragile and inflexibility,which cannot meet the requirements for arbitrary bending of next generation electronic devices.Therefore,researchers are devoted to develop new transparent conductive materials to replace ITO.In recent years,as a transparent conductive layer,metal?mainly silver and copper?nanowires have aroused great interests of researchers and industry for their high optical transmittance,super electrical conductivity and favorable flexibility.However,the high contact resistance and easy oxidation of metal nanowires severely limit their applications in optoelectronic devices.In this paper,flexible metal nanowires?silver and copper nanowires?composite transparent electrodes with high conductivity,high transmittance and excellent air stability were fabricated by constructing composite transparent electrodes.The main details and conclusions are as follows:?1?The flexible Ag NWs/ZnO composite transparent electrodes with high performance were prepared by spin-coating at low temperature.Firstly,ZnO nanoparticles?NPs?were synthesized by reduction method,and then Ag NWs and ZnO NPs dispersions were spin-coated on PET substrates.By optimizing the spin-coating cycles of Ag NWs and ZnO and sintering temperature of composite electrodes,the best Ag NWs/ZnO transparent electrodes obtained exhibit low sheet resistance?²0?/sq?and high transmittance at visible region?⁸7%at 550 nm?.The sheet resistance of Ag NWs/ZnO transparent electrodes have no obvious changes even after 30 days at room temperature or aged the condition with 300?high temperature.It can be found that the overlaid coating of ZnO NPs on Ag NWs network not only effectively improved the optical-electrical properties,smooth surface morphology,flexibility,but also enhanced the ambient and thermal stability of Ag NWs based transparent electrodes.?2?Cu NWs with uniform size were synthesized by hydrothermal method,and Cu NWs transparent electrodes were prepared by vacuum filtration method.The high-quality Cu NWs transparent electrodes were fabricated by a robust post-treatment at room temperature.Firstly,by employing a sodium borohydride?NaBH₄?treatment,the organics and oxides on surface of Cu NWs can be removed completely and thus greatly improving the conductivity of Cu NWs networks.Subsequently,by decorating the Cu NWs transparent electrodes with a dense hydrophobic DT layer,the mechanical and chemical stability of Cu NWs transparent electrodes can be greatly enhanced.By optimizing the concentration and treatment time of NaBH₄ solution and treatment time of DT-decoration layer,the best Cu NWs transparent electrodes obtained exhibit a low sheet resistance??38?/sq?and a high transmittance??83%at 550 nm?at the visible range.Finally,the DT-decorated Cu NW transparent electrodes were tested as transparent heaters and the temperature rises to 80°C under a low voltage of 5 V within 50 s,which meets the requirements of commercial defrosting.?3?The Cu NWs/rGO transparent electrodes with high conductivity,high transmittance and enhanced flexibility and stability were prepared by vacuum filtration and spray-coating method at room temperature.By employing a NaBH₄ treatment,the organics and oxides on the surface of Cu NWs are removed completely.At the same time,the GO is reduced and thus the enhance the conductivity of composite transparent electrodes.By optimizing the concentration and treatment time of NaBH₄ solution and volume of GO,best Cu NWs/rGO transparent electrodes exhibit a low sheet resistance?⁵0?/sq?associated with 83%transparency.The experimental results show that the stability of Cu NWs/rGO transparent electrodes is better than that of bare Cu NWs transparent electrodes in a constant condition with room temperature,60?or 80?.Futthermore,the conductivity of composite films remains unchanged even after 10000 inner and outer bending cycles,which lays a foundation for the application of Cu NWs in flexible electronic products.Lastly,the potential of Cu NWs/rGO transparent electrodes in heaters was demonstrated.And the foggy water vapor on transparent electrodes can be evaporated only for 8 s under a DC voltage of 8V.