In Situ Ring Opening Polymerization of High‐Performance Full‐Color CsPbX3@PDMS (X = Cl, Br, I) Nanospheres Toward Wide‐Color‐Gamut Displays

Abstract Optimizing the three‐primary‐color perovskite quantum dots (TPC PQDs) is crucial for achieving ultra‐wide color gamut displays. Although encapsulation is an effective strategy to improve the stability and optical performance of the TPC PQDs, the chemicals or environment employed in the coating procedure may attack the CsPbX 3 PQDs and generate defects, damage, and ligand loss. Herein, a mild, facile and universal hexamethylcyclotrisiloxane (D3) in situ ring opening polymerization strategy is successfully developed for efficiently synthesizing high‐brightness and extremely stable TPC CsPbX 3 @PDMS (X = Cl, Br, I) nanospheres, with particularly friendlyness for fragile red and blue. The formation of Pb─O bond between polydimethylsiloxane (PDMS) and CsPbX 3 passivates the lattice defects, resulting in photoluminescence quantum yields (PLQYs) improvement of ≈1.5 times for green and red, astonishingly 2 times for blue PQDs. Also, PDMS shell effectively blocks threats from the environment. Finally, the synthesized CsPbX 3 @PDMS nanospheres are successfully applied in fabrication of the TPC light emitting diodes (LEDs) and full‐color liquid crystal displays (LCDs), achieving impressive ultra‐wide color gamuts of 132% and 118% National Television Standards Committee (NTSC), respectively. These findings support the new strategy for synthesizing emerging full‐color perovskite nanomaterials and shows great potentieal for high color‐rendering displays.