CaY2Si2S8:Ce3+: a novel green-emitting thiosilicate phosphor for white light-emitting diodes
A novel green-emitting Ce3+-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:Ce3+ from 25 to 225 °C were performed. In addition, a white LED device was fabricated by using the green-emitting CaY2Si2S8:Ce3+ phosphor and commercially-available red-emitting CaAlSiN3:Eu2+ 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.