Preparation And Properties Of WO₃/Ag/PEI/CuSCN Multi-layers Transparent Electrode

Transparent conductive electrode is an important part of organic light-emitting diode(OLED),and its performance directly affects luminous efficiency of OLED.Therefore,it is of great significance to study the performance of electrode.In order to solve the problems of brittleness and scarcity of indium resources of indium tin oxide,a WO₃(tungsten trioxide)/Ag(silver)/PEI(Polyethyleneimine)/Cu SCN(cuprousthiocyanate)(WAPC)multi-layers electrode was proposed.The optical properties of the electrode were simulated by transfer matrix theory.WAPC multi-layers transparent electrode was prepared by spin coating and vacuum evaporation.The main contents are as follows:(1)The optical properties of electrode WO₃/Ag/Cu SCN(WAC)are simulated by transfer matrix theory,and the optimal multi-layers transparent structure is WO₃(35nm)/Ag(9nm)/Cu SCN(47nm).Its optical transmittance at 550nm is 92.7%,and the transmittance decreases with the increase of Ag(>9nm)thickness.(2)WAPC electrode was prepared on ultra-thin polyimide substrate by spin coating and vacuum evaporation.The optimal electrode structure was WO₃(35nm)/Ag(13nm)/Cu SCN(47nm).Its optical transmittance is 85%at 550nm and the sheet resistance is 6.4?/sq.(3)In order to further improve the electrode performance,Polyethyleneimine(PEI)was introduced as the seed layer of Ag layer,and Ag/PEI composite film was prepared on Cu SCN film with transmittance 71%and sheet resistance 10?/sq.Compared with the Ag prepared on Cu SCN thin film,the transmittance of Ag/PEI composite films is increased by 8%,the sheet resistance is reduced by 16?,and the Ag/PEI composite film are more uniform and smooth.(4)Through optimizing the thickness of Ag layer,the optimal laminated transparent electrode structure WO₃(35nm)/Ag(9nm)/PEI/Cu SCN(47nm)is obtained.Its optical transmittance is 90%,the sheet resistance is 10.2?/sq,and the root mean square roughness is 4.4 nm.In addition,it also showed excellent mechanical properties,and the sheet resistance remained unchanged under the 1000 bending tests(radius 1mm).