Colour tuning of core–shell fluorescent materials
Abstract
Generally, two or more phosphors are mixed to achieve multiplex colour in the fluorescence industry. However, such a simple mixture of fluorescent materials usually leads to colour discrepancy and may even affect the colour uniformity due to the distinct physicochemical properties of the different components. Fabrication of a core–shell structure is a novel strategy to prepare colour-tuned fluorescent materials. Here we report a core–shell structure made up from two phosphors, Y2O3:Eu and LnPO4, which can emit red and green light respectively. It is important to control the homogeneous and relatively low supersaturation of LnPO4 (Ln = La, Ce, and Tb) in the solution so that the precipitates of LnPO4 can deposit onto the Y2O3:Eu particles uniformly. This could result in an LnPO4 shell around the Y2O3:Eu core to form micron-sized complex particles. In the preparation of the core–shell structure, the slow hydrolysis of tripolyphosphate to release free