Interface reaction-induced fabrication of RE3Al5O12 (RE = Gd–Lu, Y) phosphor conversion plates for WLEDs

Rare earth aluminate garnets (RE₃Al₅O₁₂, REAGs) have important application values in optical fields owing to their exceptional luminescence properties, chemical stability, and thermal stability. These materials typically require thin-film configurations for applications such as solid-state lighting (phosphor-converted white LEDs), radiation detection scintillators, and laser gain media. In this study, we developed a hydrothermal reaction strategy to prepare rare earth hydroxycarbonate films (RE₂(OH)_x(CO₃)_y(NO₃)_(6−x−2y)·nH₂O, RE = Tb–Lu, Y) on sapphire substrates using rare earth nitrates and urea. Subsequent thermal treatment induced interfacial reactions, enabling the fabrication of broad-spectrum REAG (RE = Gd–Lu, Y) systems. We systematically investigated the luminescence characteristics of the REAG (RE = Tb, Y, Lu) systems. By integrating LuAG, YAG, and TbAG films with a blue LED chip, we achieved cold white light emission with a color rendering index (CRI) of Ra = 70.3. This research provides a novel approach for preparing rare earth garnet films and demonstrates their application potential in solid-state lighting.