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

SiO2 encapsulated quantum dots (QDs@SiO2) have been widely adopted for fabricating high-performance phosphor-converted light-emitting diodes (QCLEDs). However, the impact of SiO2 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@SiO2 on optical performance of QCLEDs. QDs@SiO2 nanoparticles with SiO2 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@SiO2 with 20-30-nm SiO2 shell display optimal efficiency owning to suppressed self-absorption quenching and enhanced light scattering. However, because of heat accumulation inside QDs@SiO2 at high power density, thin SiO2 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@SiO2 structure to meet application requirements of different QCLED devices.

Automated summary

The study finds that the thickness of SiO2 shell of QD@SiO2 has a significant impact on the optical performance of QCLEDs, with 20-30 nm SiO2 shell showing optimal efficiency at low power density, while 10-15 nm SiO2 shell is more favorable for reducing thermal quenching at high power density.