Development of Tb1.5Gd1.5Al5O12:Ce Single-Crystalline Film Converters for WLED Using a Liquid Phase Epitaxy Growth Method

The investigation of the structural, luminescent and photoconversion properties (color coordinates, correlated color temperature, color rendering index and luminous efficacy) of the single-crystalline films of Ce3+-doped Tb1.5Gd1.5Al5O12:Ce mixed garnet with variable film thickness was performed in this work. These film converters were grown on undoped Y3Al5O12 substrates using the liquid phase epitaxy technique. When combined directly with blue LEDs that were commercially available in the market, the developed garnet film converters were responsible for producing white light. The trend line on the color coordinate diagram was obtained for the first time for the Tb1.5Gd1.5Al5O12:Ce converters with the systematic variation in film thickness in the range of 45–82 µm. Under 464 nm blue LED excitation, the investigated converters with a thickness of 55 µm resulted in an ideal white color.