Highly Luminescent and Stable Perovskite Quantum Dots Films for Light‐Emitting Devices and Information Encryption

Abstract The inherent flexibility and excellent mechanical strength of lead halide perovskite quantum dots (LHP‐QDs) films have attracted much attention in the fields of flexible lighting, displays, non‐planar x‐ray imaging, and wearable optoelectronics. Unfortunately, the complicated synthesis process and poor stability limit its practical applications, hence there is an urgent need to develop a feasible fabrication process for films to attain high device performance. Herein, a molecular level hybridization of bridged polysilsesquioxane (BPSQ) is designed as matrix to harvest both flexibility of organics and stability of inorganics, resulting in improved interfacial compatibility between the CsPbBr₃ QDs and the matrix through chemical bond anchoring. The CsPbBr₃@3‐aminopropyl‐triethoxysilane (APTES)@BPSQ films showcase bright narrow‐band photoluminescence, with a photoluminescence quantum yield of 61% and a half‐peak full width at half maximum of <17 nm. Notably, these films demonstrate excellent environmental stability, UV resistance, water stability (experiencing only an 18% decrease in luminescence intensity after 168 h of water immersion), and high‐temperature stability (withstanding temperatures up to 500 K). Furthermore, white light‐emitting diodes (WLEDs) and anti‐counterfeiting patterns have been fabricated using CsPbBr₃@APTES@BPSQ, highlighting their wide application potential in flexible light‐emitting devices and information encryption.