Abstract
This work presents a comprehensive study of the structural, luminescent, and photoconversion properties of epitaxial composite phosphor converters based on single crystalline films of Ce(3+)-activated Ca(2-x)Y(1+x)Mg(1+x)Sc(1-x)Si(3)O(12):Ce (x = 0-0.25) (CYMSSG:Ce) garnet, grown using the liquid phase epitaxy (LPE) method on single-crystal Y(3)Al(5)O(12) (YAG) and YAG:Ce substrates. The main goal of this study is to elucidate the structure-composition-property relationships that influence the photoluminescence and photoconversion efficiency of these film-substrate composite converters, aiming to optimize their performance in high-power white light-emitting diode (WLED) applications. Systematic variation in the Y(3+)/Sc(3+)/Mg(2+) cationic ratios within the garnet structure, combined with the controlled tuning of film thickness (ranging from 19 to 67 µm for CYMSSG:Ce/YAG and 10-22 µm for CYMSSG:Ce/YAG:Ce structures), enabled the precise modulation of their photoconversion properties. Prototypes of phosphor-converted WLEDs (pc-WLEDs) were developed based on these epitaxial structures to assess their performance and investigate how the content and thickness of SCFs affect the colorimetric properties of SCFs and composite converters. Clear trends were observed in the Ce(3+) emission peak position, intensity, and color rendering, induced by the Y(3+)/Sc(3+)/Mg(2+) cation substitution in the film converter, film thickness, and activator concentrations in the substrate and film. These results may be useful for the design of epitaxial phosphor converters with tunable emission spectra based on the epitaxially grown structures of garnet compounds.