Energy transfer from VO43− to Sm3+ ions in ɑ-Sr2V2O7 phosphors for full-spectrum warm-WLED device and low-temperature luminescence lifetime thermometry

Abstract

Novel ɑ-Sr2V2O7: Sm3+ phosphors with color-tunable performance were prepared in this work. The crystal structure, photoluminescence properties, and potential applications were introduced. The efficiency of the energy transfer from the [VO4]3- tetrahedral to Sm3+ was 22.67% at a low doping content of Sm3+ (9 mol%), driven by the dipole-dipole interaction. Interestingly, the ɑ-Sr2V2O7: Sm3+ phosphors emitted a full-spectrum (400–800 nm) emission, and the corresponding chromaticity coordinates were located in a near-warm light region. In the potential applications, the warm-white lighting-emitting diode (warm-WLED) based on ɑ-Sr2V2O7: 0.03Sm3+ phosphor was fabricated and further exhibited high-quality performances with the beneficial color rendering index (CRI = 78.67) and low correlated color temperature (CCT = 2257 K) for indoor illumination. Moreover, the low-temperature (38–298 K) optical thermometry performance was also analyzed with the help of Struck and Fonger's theory. Remarkably, the relative sensitivity has an outstanding value of 3.12% K−1 at 98 K. All the above results evidence that the full-spectrum ɑ-Sr2V2O7: Sm3+ phosphors are expected to apply in full-spectrum warm-WLED devices and low-temperature luminescence lifetime thermometry.