A Novel Thermally Stable Warm White Phosphor CaYGaO₄:Dy³⁺ for Indoor Lighting Applications

Trichromatic phosphors can be blended to produce white light‐emitting diodes (WLEDs) by altering the mixing ratio, albeit with inherent limitations like inadequate thermal stability and imprecise sample proportions. In this study, a series of single‐host CaYGaO 4 :Dy 3+ (CYGO:Dy 3+ ) phosphors are synthesized using a high‐temperature solid‐state reaction method. The microstructure of prepared samples is analyzed through X‐ray diffraction, scanning electron microscope, energy dispersive X‐ray spectroscopy. The results confirm that Dy 3+ ions are effectively doped into the CaYGaO 4 (CYGO) host. The band structure and state density of CYGO are calculated based on density functional theory (DFT). Furthermore, the band gap ( E g ) was verified through the tested absorption spectra (Abs) data. In the spectra of CYGO:Dy 3+ , there are two excitations in the ultraviolet region, 347 and 364 nm, and the excitation peaks are mainly composed of 485 nm in the blue region and 570 nm in the yellow region. Finally, the phosphor is integrated with a 365 nm chip LED device, and its performance is thoroughly analyzed. The investigation confirms the promising application of CYGO:Dy 3+ as a single‐phase warm white phosphor in the realm of indoor lighting applications.