Color tunable Eu-doped CaSrNb2O7 phosphors for white light-emitting diodes and optical thermometers

Abstract

Herein, Eu-doped CaSrNb2O7 perovskites are synthesized by using the high-temperature solid-phase method, resulting in layered perovskite structure, with the space group of Cmc21 and a strong luminescence response under excitation wavelength of 314 nm. Moreover, these as-prepared CaSrNb2O7:xEu3+ (x = 0–0.15) phosphors are color-tunable. Specifically, the color changes from white to blue with raising temperature. After thermal stability testing, the fluorescence intensity ratio, maximum absolute and relative sensor sensitivity of CaSrNb2O7:xEu3+ are calculated to evaluate the thermal properties of materials. It turned out that the maximum absolute and relative sensor sensitivity are 0.043 K-1 and 0.0105 K-1, and the temperature resolution is as low as 0.0286K, respectively. It suggests that the high sensitivity and excellent resolution of CaSrNb2O7:xEu3+ make it a promising candidate for optical thermometers.