Selectively Tunable Luminescence of Perovskite Nanocrystals Embedded in Polymer Matrix Allows Direct Laser Patterning

Abstract Cesium lead halide perovskite nanocrystals (NCs) have gained enormous attention as promising light‐emitting and light‐converting materials. Most of their applications require embedding NCs in various matrices, which is a challenging task due to their low stability, especially in the case of red‐emitting CsPbI₃ NCs. In this work, a new approach is proposed allowing the formation of red‐emitting perovskite NCs by anion exchange induced directly inside a solid polymer matrix using green‐emitting CsPbBr₃ NCs as templates and iodododecane as an iodine source. Moreover, a simple and efficient route to photo‐assisted termination of the anion exchange reaction in the polymer composite after reaching desired optical properties is demonstrated. The findings allow the authors to pattern a thin composite film with an ultrashort UV laser resulting in a selective generation of green‐ and red‐emitting features with a 15 µm resolution.