Core-shell-core heterostructural engineering of Y2O3:Eu3+/MCM-41/YVO4:Eu3+ for enhanced red emission and tunable, broadened-band response to excitation

Abstract

For the first time, a hierarchical phosphor Y2O3:Eu3+/MCM-41/YVO4:Eu3+, with a core–shell-core heterostructure, is presented in this study. Synergistically bridging the phosphors Y2O3:Eu3+ (as an inner core) and YVO4:Eu3+ (as an outer core) by amorphous SiO2, i.e., MCM-41 (with ordered mesoporous channels) leads to the generation of the core–shell-core heterostructure with enhanced red emission and tunable, broadened-band response to excitation. The novel structure of the core–shell-core hierarchical material is clarified through various characterization methods including X-ray diffraction analysis, transmission electron microscopy, selected-area electron diffraction and N2 adsorption–desorption measurements. Significantly, through temperature-dependent fluorescence investigation, it is found that our core–shell phosphor (Y2O3:Eu3+/MCM-41) exhibits impressive fluorescence stability against temperature variation (27–227 °C) due to the protective effect resulting from MCM-41. By contrast, lowered stability can be noted for the core–shell-core phosphor (Y2O3:Eu3+/MCM-41/YVO4:Eu3+), especially when the temperature is higher than 100 °C, owing to the outer core (YVO4:Eu3+ nanoparticles) that is directly exposed to heat. Such a kind of luminescent materials holds substantial promise for labeling the organisms that are vulnerable to short-wavelength UV light irradiation. Additionally, potential intelligent systems can be expected to be designed on the basis of the fluorescence mutation as triggered by the temperature of 100 °C.