Full‐Color Micro‐Displays Utilizing High‐Stability Pure Red Light Perovskite Quantum Dot Nanopapers

ABSTRACT Red perovskite quantum dots are critical for the next generation of micro‐LED displays, yet their commercialization is thwarted by poor color purity and operational instability. Here, we report a novel, one‐step fabrication of a flexible perovskite quantum dot nanopaper (PQDnP) that overcomes these challenges through a synergistic, multi‐scale stabilization mechanism. We replace conventional surface ligands with a dual‐component system: a sustainable cellulose nanocrystal matrix acts as a robust, thermally insulating scaffold, while a phenethylamine cation provides atomic‐level surface passivation and induces the formation of a protective quasi‐2D perovskite shell. This hierarchical design yields pure‐red PQDnPs with a stable photoluminescence (PL) at 621 nm and a ultra‐narrow spectral linewidth of less than 30 nm. The resulting nanopaper demonstrates outstanding robustness, including superior thermal stability and excellent photostability, retaining 74% of its PL intensity after 24 h under harsh blue‐light irradiation (150 mW/cm 2 ). By integrating the PQDnP as a color converter with a vertically stacked blue/green μ‐LED array, we demonstrate a white‐light device with a high system external quantum efficiency of 4.5% and a high peak luminance of over 26,000 cd/m 2 . This bio‐inspired, scalable approach provides a practical solution to the persistent “red gap” problem, paving the way for high‐fidelity perovskite‐based micro‐displays.