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

A series of intense green/yellow phosphors Ca 3 SiO 4 Cl 2 :Eu 2+ ,Mn 2+ 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 Ca 3 SiO 4 Cl 2 :Eu 2+ ,Mn 2+ 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 5d 4f transition of the Eu 2+ ion and the 4 T 1g 4 G 6 A 1g 6 S transition of the Mn 2+ ion, respectively. The lifetime of the Eu 2+ ion decreases with increasing the concentration of the Mn 2+ ion, strongly supporting an efficient energy transfer from Eu 2+ to Mn 2+ . By combining with near-ultraviolet 395 nm InGaN chips, intense yellow light-emitting diodes LEDs with a much lower ultraviolet light leakage were successfully fabricated based on the Ca 3 SiO 4 Cl 2 :Eu 2+ ,Mn 2+ phosphor, and intense white LEDs were made based on a blend of blue chlorophosphate phosphor and the green/yellow phosphor Ca 3 SiO 4 Cl 2 :Eu 2+ ,Mn 2+ . The color coordinate, correlated color temperature T c , general color-rendering index R a , and luminous efficiency of the fabricated white LEDs are 0.