Phase‐Transfer Catalysis Toward Surface‐Reconstructed Perovskite Nanocrystals Enabling Efficient Perovskite LEDs and Micropatterns

ABSTRACT Metal halide perovskite nanocrystals (NCs) are promising materials for next‐generation ultrahigh‐definition displays through achieving efficient micropattern light‐emitting diodes (LEDs). However, the micro‐devices exhibited inferior electroluminescent (EL) efficiency, which likely arose from the fact that effective surface reconstruction of the NCs is often impeded by challenges in defect management. In this work, we developed a phase‐transfer catalytic (PTC) strategy for the surface reconstruction of CsPbI 3 NCs, utilizing tetrabutylammonium iodide (TBAI) as a catalyst to mediate the incorporation of the solid‐phase ligand guanidinium iodide (GuI). The mechanism is rooted in a specific molecular interaction between TBAI and GuI, which disrupts the strong hydrogen‐bonding network of GuI molecules, effectively inhibits excessive GuI accumulation, and prevents micelle formation. As a result, the LEDs achieved peak external quantum efficiency (EQE) of 26.5% and exhibited more than a tenfold increase in operational lifetime. Furthermore, this methodology enabled the fabrication of high‐resolution micro‐LEDs with 1588 pixels per inch (PPI) and an EQE of 20.6%, which exhibiting bright and stable electroluminescence, further highlighting the versatility and scalability of the approach for advanced display technologies.