Optical and structural approaches for improved luminance distribution and enhanced efficiency of organic light emitting diodes

Abstract We combined cavity based optical method and polymer based structural approach to achieve efficiency enhancement and widened luminance distribution of organic light emitting diodes. Cavity method was implemented by adjusting the thickness of the hole transport layer and using a ITO-Metal-ITO transparent electrode. Utilizing the lateral phase separation of immiscible polystyrene/ polyethylene glycol binary system, we have fabricated an aperiodic protruding structure. The application of the two methods yielded two fold efficiency enhancement and widened luminance distribution. To be specific the external quantum efficiency increased from 8.9% to 17.9%.

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