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.
Sheng et al. (Wed,) studied this question.