In this study, a simple spraying method is used to prepare the transparent conductive films(TCFs) based on Ag nanowires(AgNWs). Polyvinylpyrrolidone(PVP) is introduced to modify the interface of substrate. The transmittance and bending performance are improved by optimizing the number of spraying times and the solution concentration and controlling the annealing time. The spraying times of 20, the concentration of 2 mg/m L and the annealing time of 10 min are chosen to fabricate the PVP/AgNWs films. The transmittance of PVP/AgNWs films is 53.4%—67.9% at 380—780 nm, and the sheet resistance is 30 ?/□ which is equivalent to that of commercial indium tin oxide(ITO). During cyclic bending tests to 500 cycles with bending radius of 5 mm, the changes of resistivity are negligible. The performance of PVP/Ag NW transparent electrodes has little change after being exposed to the normal environment for 1 000 h. The adhesion to polymeric substrate and the ability to endure bending stress in AgNWs network films are both significantly improved by introducing PVP. Spraying method makes AgNWs form a stratified structure on large-area polymer substrates, and the vacuum annealing method is used to weld the AgNWs together at junctions and substrates, which can improve the electrical conductivity. The experimental results indicate that PVP/Ag NW transparent electrodes can be used as transparent conductive electrodes in flexible organic light emitting diodes(OLEDs).
A transparent 3-mercaptopropyl trimethoxysilane(MPTMS)/Ag/MoO3 composite anode is introduced to fabricate green organic light-emitting diodes(OLEDs). Effects of the composite anode on brightness and operating voltage of OLEDs are researched. By optimizing the thickness of each layer of the MPTMS/Ag/MoO3 structure, the transmittance of MPTMS/Ag(8 nm)/Mo O3(30 nm) reaches over 75% at about 520 nm. The sheet resistance is 3.78 ?/□, corresponding to this MPTMS/Ag(8 nm)/MoO3(30 nm) structure. For the OLEDs with the optimized anode, the maximum electroluminescence(EL) current efficiency reaches 4.5 cd/A, and the maximum brightness is 37 036 cd/m2. Moreover, the OLEDs with the optimized anode exhibit a very low operating voltage(2.6 V) for obtaining brightness of 100 cd/m2. We consider that the improved device performance is mainly attributed to the enhanced hole injection resulting from the reduced hole injection barrier height. Our results indicate that employing the MPTMS/Ag/MoO3 as a composite anode can be a simple and promising technique in the fabrication of low-operating voltage and high-brightness OLEDs.
