Highly Stabilized Gradient Alloy Quantum Dots and Silica Hybrid Nanospheres by Core Double Shells for Photoluminescence Devices

This Letter reports the synthesis approach and application of colloidal suspensions containing gradient alloy quantum dots (QDs) and silica hybrid spheres with improved thermal and photostability, invisible QD aggregation, and high material compatibility. These hybrid nanospheres are characterized by using silica spheres as cores, adsorbing QDs as one shell, and then coating a silica layer as another shell (termed SiO2-QD-SiO2). They were synthesized by using Stober and adsorption methods. The experimental conditions affecting the optical properties were fully investigated. A light-guiding microstructure array (LGMA) was fabricated and tested for photoluminescence demonstration. After accelerated aging tests for 240 h under 85 degrees C, 40% relative humidity, and 450 nm blue light excitation, the luminance of the SiO2-QD-SiO2 LGMA remained stable, which was 1.6 times greater than that of untreated QD samples. This structure with long-term photothermal stability could pave the way for displays or lighting applications.