Effect of the Electronic Structure on the Stability of CdSe/CdS and CdSe/CdS/ZnS Quantum-Dot Phosphors Incorporated into a Silica/Alumina Monolith

In this letter, we prepare ultrastable quantum-dot (QD)-based phosphors. Furthermore, we find that type I CdSe/CdS/ZnS QDs are fairly stable during the thermal annealing process of a QD–SiO2/Al2O3 monolith (SAM) phosphor, but quasi-type II CdSe/CdS QDs easily lose their emission possibly because the delocalized electrons to the shell are more susceptible to being captured by the surface trap sites. The light-emitting diode (LED) encapsulated with a CdSe/CdS/ZnS QD–SAM phosphor on the blue LED chip can maintain approximately 90% of its initial intensity after 450 h, in contrast, the light intensity of the reference LED using a CdSe/CdS/ZnS QD decreases to approximately 41%.