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

Cesium lead halide (CsPbX 3; 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 CsPbBr 3 QDs, red-emitting CsPbI 3 QDs suffer from irreversible phase transitions induced by environmental stresses, leading to performance degradation that limits their applications in LEDs. The preparation of CsPbI 3 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 Zn 2+ doping concentration, we successfully fabricated Zn 2+ -doped CsPbI 3 /PVDF composite films with excellent luminescent properties, achieving a PLQY of 86%. Furthermore, by integrating the Zn 2+ -doped CsPbI 3 /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 CsPbI 3 QDs for white-light LED applications.