Broadband Yellow Phosphor Discovered by Single-Particle Analysis Based on Fluorescence Microscopy, Scanning Electron...

The discovery of new, efficient, and stable inorganic phosphors excited by near-ultraviolet (n-UV) light is of great significance for the realization of high-performance healthy lighting and special lighting. The traditional methods to find new phosphors are usually time-consuming, laborious, and inefficient. Here, a simple and efficient method to find new phosphors using fluorescence microscopy, scanning electron microscopy (SEM), cathodoluminescence (CL), and energy-dispersive X-ray spectroscopy (EDS) is proposed. At the same time, a phosphor Ca₅BaP₄O₁₆ (CBPO): Eu²⁺ found by this method is reported. Under 365 nm excitation, the optimal phosphor shows an ultrabroad yellow emission band with a peak at 573 nm and a full width at half-maximum of 164 nm. Compared with most phosphate phosphors, CBPO: Eu²⁺ shows good thermal stability. The emission intensity at 150 °C can maintain 61.4% of the initial value at room temperature. Importantly, the quantum efficiency of the optimal CBPO: Eu²⁺ sample is 66.2%. In addition, a WLED lamp was obtained by combining CBPO: Eu²⁺ and BAM: Eu²⁺ phosphors with a 365 nm n-UV chip, which generated high-performance white light with a correlated color temperature of 7115 K and a color rendering index of 89.4. It is certain that the new method is very effective and useful for the discovery of new phosphors.