Pb(OH)2 Precursor and La3+ 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 PbBr2 lead source, successfully reducing the raw material cost by nearly 50%. At the same time, it significantly improved the optical performance of CsPbBr3@glass by reducing the formation of bromine vacancies. By further introducing La3+, the prepared La3+@CsPbBr3@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 CsPbBr3&CsPbBr1I2@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.