Strategy for the fabrication of perovskite-based green micro LED for ultra high-resolution displays by micro-molding process and surface passivation

Perovskite is an emerging material for light-emitting diode (LED) applications, and the external quantum efficiency (EQE) of perovskite LEDs (PeLEDs) has rapidly improved compared to state-of-the-art organic and quantum-dot LEDs. In addition, mini/micro LEDs have attracted significant attention as next-generation displays owing to their desirable characteristics such as low power consumption, high contrast ratio, high brightness, fast response speed, and high efficiency. In this study, we successfully develop a high-resolution large-area soft lithography method for the micro-patterning of a perovskite emissive layer. This approach is based on micro- and capillary-molding processes, and the highest achievable pattern resolution is 5 μm. In addition, to further improve the efficiency and stability of the micro PeLEDs, various polymers with different functional groups are applied to passivate the perovskite surface. Consequently, the CsPbBr3–polyacrylonitrile (PAN) micro PeLEDs demonstrate the optimum performance and high stability, with the maximum EQE of 12.8 %, maximum luminance of 10737 cd m−2, and half-life of 993 s with 1270 pixels per inch (ppi). Our work demonstrates the feasibility of micro-patterned perovskites as well as the potential of perovskites for use in ultra high-resolution displays (UHDs).