Enhanced color rendering index and thermal stability of Ca2GdNbO6: Dy3+ phosphors by co-doping Sm3+ ions

Abstract

Nowadays, white light-emitting diodes (WLEDs) converted from single-phase white light-emitting phosphors are a popular subject in solid-state lighting. Dy is one of the most widely used activator ions in single-phase white light-emitting phosphors. However, its application in solid-state lighting is limited due to the lack of a red light component. Therefore, this work synthesized single-phase white light-emitting CaGdNbO: 0.05Dy, Sm (CGNO: 0.05Dy, Sm) phosphors with a double perovskite structure. A detailed study was conducted on the occupancy of co-doped Dy-Sm ions in the CGNO lattice and the microstructure of the sample. Simultaneously, the luminescence performance, concentration quenching mechanism, energy transfer, and thermal stability of CGNO:0.05Dy, Sm phosphors were discussed. The results indicate that the phosphors have stable physical and chemical properties and excellent optical properties. Under 363 nm excitation, emission peaks of both Dy and Sm were observed in the emission spectrum, indicating that Sm compensates for the insufficient red light component in the samples. In addition, the CIE chromaticity coordinates (CIE) of the CGNO: 0.05Dy, Sm samples and the luminescence stability in water were studied. Finally, a WLED device with a high color rendering index Ra = 85.4) and low correlated color temperature (CCT = 3135 K) was prepared by combining a 365 nm chip with the CGNO: 0.05Dy, 0.05Sm phosphor. The research confirmed that single-phase white light-emitting CGNO: 0.05Dy, Sm phosphors have potential application prospects in the field of WLEDs.