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).