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. Dy3+ 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 Ca2GdNbO6: 0.05Dy3+, ySm3+ (CGNO: 0.05Dy3+, ySm3+) phosphors with a double perovskite structure. A detailed study was conducted on the occupancy of co-doped Dy3+-Sm3+ 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:0.05Dy3+, ySm3+ 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 Dy3+ and Sm3+ were observed in the emission spectrum, indicating that Sm3+ compensates for the insufficient red light component in the samples. In addition, the CIE chromaticity coordinates (CIE) of the CGNO: 0.05Dy3+, ySm3+ 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: 0.05Dy3+, 0.05Sm3+ phosphor. The research confirmed that single-phase white light-emitting CGNO: 0.05Dy3+, ySm3+ phosphors have potential application prospects in the field of WLEDs.