Research On Preparation And Application Of Graphene/Metallic Network Hybrid Films Transparent Electrode

Flexible electronics have achieved a great progress, such as flexible display, solar cells, OLED and touch screens, researchers and enterprises are paying more attention to new types of transparent electrodes have the advantages of flexible 、 low cost and excellent optical and electrical properties. Currently, ITO(Indium Tin Oxide) film is commonly used as transparent electrode by magnetron sputtering technology, but this material is brittleness and expensive, not suitable for flexible optoelectronic devices.Recently, the ITO replacement such as graphene, carbon nanotubes and metallic mesh has been opening new directions. However, the further development and application of new types of transparent electrodes are limited due to some technical factor. First,graphene films synthesized by chemical vapor deposition(CVD) are almost transparent,but the conductivity of graphene is poor due to its crystal structure. Second, metallic mesh has better conductivity, but too small holes of mesh lead to lower transmission.When the holes are too large, mesh is independent as a transparent electrode to fabricate optoelectronic devices.Based on two limitations, we combine the advantages of both graphene and metallic mesh. Keeping on the high transmission of metallic mesh, by combining monolayer graphene films with metallic network, it not only reduces the resistance of polycrystalline graphene but also makes metallic mesh to be continuous hybrid films.We conduct a systematic study on its structure、properties and application based on graphene/metallic mesh hybrid films as transparent electrode.Large area monolayer graphene films were synthesized by chemical vapor deposition. Metal catalyst as substrate for growth and was annealed at high temperature,carbon sources were resolved into carbon atoms and deposited on polycrystalline substrate. Carbon atoms nuclear on the substrate and grow two-dimensional graphene.Graphene was transferred by two different support carrior mode. We observed surface morphology and defect of graphene based on different characterization means, and characterized graphene domain size by thermal oxidation and tested oxidation resistance of graphene, so we confirmed that graphene is the ideal metal protective layer. We also investigated graphene layers-dependent optical and electrical properties.We expand the application of network cracks mask technique and use it to preparethe uniform metallic mesh. First, We used emulsion or gel that is cheap, easy to prepare,non-toxicity and non-pollution to fabricate network cracks mask, and deposited metal layer on the template by sputtering technology, then lifted off the template with solution process and obtained the excellent properties of metallic mesh. However, on some special substrate, we can not form cracked template on it. So we proposed a new approach based on SiO2 transition layer and use it to transfer metallic mesh on the target substrate. We also investigated light-transfer characteristic of metallic mesh.Combining the advantages of CVD graphene and metallic mesh, graphene/metallic mesh hybrid films transparent electrode was made by composite mode. We systematically studied the characteristics of hybrid films transparent electrode, such as photoelectric properties, mechanical flexibility and folding. We also tested thermal oxidation stability based on graphene/oxidizable metal mesh hybrid films, and it provide the important significance for the development and application of low-cost transparent electrode. Finally, graphene/metallic mesh hybrid films as transparent electrode was integrated with organic light-emitting diode, and the optoelectronic properties of devices were measured and analyzed.