Study of Optical and Thermal Properties of SiO2 Encapsulated CdSe/ZnS Core–Shell Quantum Dots

SiO ₂ encapsulated quantum dots (QDs@SiO ₂ ) have been widely adopted for fabricating high-performance phosphor-converted light-emitting diodes (QCLEDs). However, the impact of SiO ₂ thickness on the optical properties of QDs in QCLEDs remains largely unexplored. In this work, we studied the combined effects of light scattering, heat accumulation, and concentration quenching of QD@SiO ₂ on optical performance of QCLEDs. QDs@SiO ₂ nanoparticles with SiO ₂ thickness of 10–60 nm were developed to perform the experimental tests and optical and thermal simulations. Our study reveals that at low power density, QD@SiO ₂ with 20–30-nm SiO ₂ shell display optimal efficiency owning to suppressed self-absorption quenching and enhanced light scattering. However, because of heat accumulation inside QDs@SiO ₂ at high power density, thin SiO ₂ shell (10–15 nm) is more favorable to reduce thermal quenching and maintain luminous efficiency of QCLEDs. This study provides guidance for the development of appropriate QDs@SiO ₂ structure to meet application requirements of different QCLED devices.