CaY2Si2S8:Ce~(3+): a novel green-emitting thiosilicate phosphor for white light-emitting diodes

摘要

A novel green-emitting Ce~(3+)-doped CaY2Si2S8 thiosilicate phosphor was synthesized by using solid-state methods in a sealed silica ampoule. This compound could be excited over a broad range from UV to blue light (400-450 nm) and generated a broadband emission peaking at ~495 nm, with a quantum efficiency of ~57%, which is promising for solid-state lighting applications. Temperature-dependent optical measurements of CaY2Si2S8:Ce~(3+) from 25 to 225 °C were performed. In addition, a white LED device was fabricated by using the green-emitting CaY2Si2S8:Ce~(3+) phosphor and commercially-available red-emitting CaAlSiN3:Eu~(z+) pumped with a 450 nm blue chip. The CRI value and CCT were measured to be 91-95 and 3800-8600 K, respectively, showing promising potential for solid-state lighting applications. The preparation, spectroscopic characterization, quantum efficiency, decay lifetime, thermal stability, and related LED device data are also presented.