Sm3+ doped Ca3Y(AlO)3(BO3)4: A near-UV pumped orange-red phosphor with high thermal stability

Rare-earth-ion-activated borate phosphor is an intensive topic in the lighting field due to the thermally high stability and excellent luminescence efficiency. Herein, a sequence of borate phosphors: Ca3Y(AlO)3(BO3)4:x mol% Sm3+ were successfully prepared using a conventional solid-state method. We demonstrate that the sample is a monoclinic crystal system with the P63/m space group by analyzing the crystal structure and Rietveld refinement. In addition, the ultraviolet-visible-near-infrared (UV–VIS–NIR) spectra and the first-principles calculations reveal that the Ca3Y(AlO)3(BO3)4 host can provide an excellent band-gap environment (Eg=4.34 eV) for the luminescent center. Thereafter, the analysis of fluorescence spectra shows that the excitation spectrum consists of a series of peaks, among which the 405 nm peak formed by the 6H5/2→4F7/2 transition of Sm3+ plays a dominant role. From the perspective of the emission spectrum, the 4G5/2→6H7/2 (615 nm) transition is most significant among the four narrow emission bands appeared in the visible region. The concentration quenching occurs when the optimal doping concentration (6 mol%) of Sm3+ is exceeded, and the quenching mechanism is the dipole-dipole interaction. The temperature-dependent luminescence of the Ca3Y(AlO)3(BO3)4:6 mol% Sm3+ sample reveals that 97 % of the initial intensity is still maintained at 483 K, suggesting outstanding thermal stability. Beyond that, the orange-red chromaticity coordinate (0.602, 0.396), high color purity (80 %), and ideal correlated color temperature (1700 K) indicate that Ca3Y(AlO)3(BO3)4: Sm3+ phosphor is an excellent candidate as a red phosphor for converting tri-phosphors to white light-emitting-diodes (LEDs) lighting.