An Intense Green/Yellow Dual-Chromatic Calcium Chlorosilicate Phosphor Ca[sub 3]SiO[sub 4]Cl[sub 2]:Eu[sup 2+]–Mn[sup 2+] for Yellow and White LED

Abstract

A series of intense green/yellow phosphors was synthesized by a high-temperature solid-state reaction. Their luminescent properties were characterized by means of powder diffuse reflection, photoluminescence excitation and emission spectra, and lifetime and temperature-dependent emission spectra in the temperature range of 10–450 K. The phosphors show intense broad absorption bands between 250 and 450 nm, matching well with the near-ultraviolet (380–420 nm) emission band of InGaN-based chips, and exhibit two dominating bands situated at 512 and 570 nm, ascribed to the allowed transition of the ion and the transition of the ion, respectively. The lifetime of the ion decreases with increasing the concentration of the ion, strongly supporting an efficient energy transfer from to . By combining with near-ultraviolet InGaN chips, intense yellow light-emitting diodes (LEDs) with a much lower ultraviolet light leakage were successfully fabricated based on the phosphor, and intense white LEDs were made based on a blend of blue chlorophosphate phosphor and the green/yellow phosphor . The color coordinate, correlated color temperature , general color-rendering index , and luminous efficiency of the fabricated white LEDs are (0.3281, 0.3071), 6065 K, 84.5, and 11 lm/W, respectively.