Patterning‐Induced Encapsulation of Stable Perovskite Quantum Dots with Controllable Morphology for Information Encryption

Abstract Perovskite quantum dots (PQDs) are promising materials for photonic and optoelectronic devices, relying on efficient and reliable patterning methods. However, the complex patterning process and poor stability of PQDs restrict their practical applications. Here, a patterning‐induced encapsulation strategy (PIE‐PQDs) is demonstrated for directly patterning PQDs into a thin polystyrene (PS) film. The prepared PQDs@PS composite film displays excellent air stability (30d, 92%), UV resistance (30d, 85%), and water resistance (30d,88%). Notably, even in harsh environments such as acid/alkali/alcohol aqueous solution, the composite film still preserves high luminescence. A binary solvent engineering strategy is induced to precisely control the distribution of PQDs inside the polymer film, resulting in morphologically controllable PQDs@PS microstructures for optical information encryption. Patterned PQDs@PS composite film can be compatible with diverse substrates including silicon, glass, paper, and plastic with the feature of optical information encryption. This method shows a universal in situ protection approach for patterning and integrating PQDs on flexible substrates, offering significant potential for display, optical data storage, information encryption, and anti‐counterfeiting.