Realization of Organic EL Devices without ITO Transparent Electrodes

为了实现无透明ITO电极的有机电致发光器件，进行了实验和理论研究。制备在结构中心具有有机发光层的金属-绝缘体-金属（MIM）结构，并测量它们的发射特性。观察到~25的强度增强，与理论估计吻合良好。强度增强可以很好地解释在MIM结构中的对称表面等离子体激元介导的光发射。对实际发光器件的模拟结果表明，当用Ag电极代替ITO电极时，光提取效率大大提高。目前的结果表明，具有高效率的有机发光器件可以构建没有ITO电极。

In order to realize organic light emitting devices without transparent ITO electrodes, experimental and theoretical studies were performed. Metal-Insulator-Metal (MIM) structures having an organic light emitting layer at the center of the structures were prepared and their emission properties were measured. An intensity enhancement of ~25 was observed in good agreement with theoretical estimates. The intensity enhancement can be well explained in terms of light emission mediated by symmetric surface plasmon polaritons in the MIM structure. Results of simulations for realistic light emitting devices indicate that the light-extraction efficiency is greatly enhanced when an ITO electrode is replaced by an Ag electrode. The present results suggest that organic light emitting devices with high efficiencies can be constructed without ITO electrodes.