Quantum Dots Electrostatically Adsorbed on the Surface of SiO₂ Nanoparticle-Decorated Phosphor Particles for White Light-Emitting Diodes with a Stable Optical Performance

White light-emitting diodes (WLEDs) based on phosphor and quantum dots (QDs) have attracted worldwide attention. Phosphor and QDs with different physical characteristics are distributed unevenly in a polymer matrix, resulting in the spectrum changes of the phosphor-QD-based WLEDs (PQ-WLEDs). Aiming for a similar distribution of QDs and phosphor in the matrix, we proposed the phosphor/SiO2/QD (PSQ) composite particles in which negatively charged QDs are electrostatically adsorbed on the surface of phosphor particles decorated with positively charged SiO2. The PSQ composite particles retained a high quantum yield of 77.6%. PSQ-WLEDs with varied standing times of the uncured PSQ-added silicone showed stable spectra with stable optical parameters. For comparison, the spectra of PQ-WLEDs with untreated phosphor and QDs obviously changed with the standing time. Specifically, the LE, CCT, and CRI of PSQ-WLEDs using Dow corning OE 180 silicone only changed by 1.7, 3.3, and 3.9%, respectively, after a long sufficient standing time; however, the LE, CCT, and CRI of PQ-WLEDs using the same silicone changed by 9, 5.4, and 10%, respectively. This optical instability in PQ-WLEDs resulted from the difference between the distribution of phosphor and QDs in the mixed silicone matrix after standing. However, the distribution of phosphor and QDs in PSQ-WLEDs was always the same with each other due to the composite structure. Applying the PSQ composite particles in WLEDs, we can easily attain highly optical consistent phosphor-QD-based WLEDs and provide an efficient control of product quality.