Zn ²⁺ -Doped CsPbI ₃ /PVDF Composite Films with Enhanced Stability and Photoluminescence Quantum Yield for White-Light LED Applications

Cesium lead halide (CsPbX₃; X = I, Br, Cl) perovskite quantum dots (PQDs), owing to their outstanding optoelectronic properties, are regarded as highly promising color conversion layer materials for next-generation wide-color-gamut display technologies. Unfortunately, compared with the increasingly mature production process of green-emitting CsPbBr₃ QDs, red-emitting CsPbI₃ QDs suffer from irreversible phase transitions induced by environmental stresses, leading to performance degradation that limits their applications in LEDs. The preparation of CsPbI₃ QDs with both high photoluminescence quantum yield (PLQY) and stability remains a significant challenge. In this study, based on a low-temperature in situ crystallization process, we propose a synergistic optimization strategy combining metal ion doping and ligand engineering. By introducing phenethylammonium iodide (PEAI) as a surface ligand, we effectively reduced the defect density on the QDs surfaces, thereby enhancing luminescence. Meanwhile, through systematic optimization of Zn²⁺ doping concentration, we successfully fabricated Zn²⁺-doped CsPbI₃/PVDF composite films with excellent luminescent properties, achieving a PLQY of 86%. Furthermore, by integrating the Zn²⁺-doped CsPbI₃/PVDF composite film with a green-emitting film, we constructed a dual-emissive-layer architecture and successfully fabricated a white-light-emitting device driven by a blue light-emitting diode (LED). The device exhibited an outstanding wide color gamut (121% of the National Television System Committee standard and 91% of Rec. 2020), along with excellent operational stability, highlighting the promising potential of CsPbI₃ QDs for white-light LED applications.