A novel blue emitting phosphor LaScO3:Bi3+ for white LEDs: high quantum efficiency, high color purity and excellent thermal stability

Abstract

Series of blue phosphors La1-xBixScO3 (x = 0–0.6) (LSO) were synthesized by the high temperature solid state method. Under the 365 nm near ultraviolet (NUV) irradiation, when the value of x is increased, the phosphor can emit blue from deep to shallow. The LSO phosphor presents an internal quantum efficiency of up to 98%, high color purity of 92.26% as well as excellent thermal stability. When x ≥ 0.2, Bi3+-doped phosphors have diverse FWHM ranging from 153 nm to 43 nm. Especially, when x = 0.5, the material shows an abnormal thermal quenching, and emission intensity at 573K can reach 128.3% of that at room temperature. The white light emitting diode (LED) was fabricated by combining the NUV LED chip (370 nm) with a mixture of LSO:0.007Bi3+ along with green Y3(Al,Ga)5O12:Ce3+ and red CaSiAlN3: Eu2+ phosphors, which show a high color rendering index Ra = 90.2, a low correlated color temperature CCT = 3999 K. The results demonstrate that LSO phosphor has potential application in the field of white LEDs.