Perovskite Anion Exchange: A Microdynamics Model and a Polar Adsorption Strategy for Precise Control of Luminescence Color

Abstract Inorganic perovskite quantum dots (QDs) have natural advantages in the field of light‐emitting diodes (LEDs) because of their high color purity and tunability in a wide range. However, when manufacturing efficiently mixed‐anion perovskite QDs (CsPbBr x I 3− x ) to meet the requirements of the pure red color standard in the display field (≈630 nm), results are difficult to control accurately due to the lack of exploration of its microscopic mechanism. Here, a microdynamics model is constructed for anion exchange dominated by vacancies which revealed the key role of polar solvent in reducing the surface energy barrier of anions through first‐principle calculations. Besides, a polar solvent construct in situ anion exchange channels method is proposed. Then, the precise control of anion exchange is demonstrated, and the precise regulation spectrum of the whole red‐light range (600–680 nm) is achieved. Finally, various QD LEDs (QLEDs) based on these tunable QDs are fabricated and exhibit excellent photoelectric performance in the main red range (620–680 nm). Among them, the champion QLEDs, have peak external quantum efficiency (EQE) of 16.3% at 633 nm and peak EQE of 18.2% at 646 nm, showing potential in meeting the requirements of display standard.