High-refractive-index polymer with silver nanowires for enhancing light outcoupling efficiency of ITO-free organic light-emitting diodes
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초록
내용
We develop the high-performance internal light-outcoupling (HRLOC) system based on the highrefractive index polyimide (PI) and metal oxide nanoparticles for organic light-emitting diodes (OLEDs) with silver nanowires (AgNWs). The spontaneously formed nanobump structures, high refractive index, and light-scattering properties of HRLOC significantly enhance the light-extraction efficiency of OLEDs. Not only do the outcoupling structures improve the light-extraction efficiency, but also remarkably enhance the electrical properties of OLEDs. The power efficiency of the AgNW-based OLEDs with PI is improved by a factor of 1.31 compared to the reference device with indium tin oxide (ITO) transparent electrode at a luminance of 20 000 cd/m2. The efficiency is further improved by incorporating TiO2 nanoparticles into the PI matrix by a factor of 1.69. We believe that the light-outcoupling structures developed here have great potential for efficient, low-cost, and flexible ITO-free OLEDs.