Polarized and Directional Electroluminescence from Organic Light‐Emitting Devices by Using a Bifunctional Meta‐Electrode

Abstract Organic light‐emitting devices (OLEDs) with polarized and directional emission are highly desired for their promising applications in optical imaging, optical communication, and immersive visual technologies. Existing implementation methods based on free space bulk optical elements suffer from significant power loss, limiting their practical applications. Here, a bifunctional meta‐electrode is proposed by integrating a metasurface consisting of Ag periodic corrugations onto the indium tin oxide (ITO) anode to simultaneously realize the functions of charge carrier injection and photon management in the OLEDs. Highly polarized and directional light emission is demonstrated while maintaining a high device efficiency using the meta‐electrode. The electroluminescence with a polarization extinction ratio of 5 is achieved by judiciously engineering the polarization‐dependent Purcell factor of the resonant cavity constructed by the meta‐electrode. Meanwhile, the directional light emission with a divergence angle of 10° can be obtained by the efficient out‐coupling of surface plasmon‐polariton mode. The light beam can be collimated in one direction by using 1D nanogratings and in two directions by using 2D nanopillars, respectively.