Pb(OH) ₂ Precursor and La ³⁺ Doping Synergy: Polyethylene Terephthalate-Encapsulated Quantum Dot Films Achieve Low-Cost and High-Stability Backlight Display

Perovskite quantum dots (PQDs) are widely used in the backlight field of liquid crystal displays (LCDs) due to their narrow-band emission and high color purity. However, their high cost and insufficient stability seriously restrict the industrialization process. This study innovatively adopted the environmentally friendly Pb(OH) 2 to replace the traditional PbBr 2 lead source, successfully reducing the raw material cost by nearly 50%. At the same time, it significantly improved the optical performance of CsPbBr 3 @glass by reducing the formation of bromine vacancies. By further introducing La 3+, the prepared La 3+ @CsPbBr 3 @glass achieved a PLQY increase from 48 to 86%, and maintained a PL intensity of 87% under harsh conditions (60 °C, 90% RH, and continuous exposure to 8000 nit blue light for 40 days), breaking through the stability bottleneck. The color gamut of the CsPbBr 3 &CsPbBr 1 I 2 @glass@PET light conversion film developed on this basis is 94.75% of the NTSC 1953 standard and 70.74% of the Rec.2020 standard. When they are applied to LCD screens, they significantly enhance color performance. It provides an efficient, stable, and low-cost industrial solution for quantum dot film technology.