Novel Cyan-Green-Emitting Bi<sup>3+</sup>-Doped BaScO<sub>2</sub>F, R<sup>+</sup> (R = Na, K, Rb) Perovskite Used for Achieving Full-Visible-Spectrum LED Lighting
Mingsheng Cai, Tianchun Lang, Tao Han, Damir Valiev, Shuangqiang Fang, Chaozhong Guo, Shuangshuang He, Lingling Peng, Shixiu Cao, Bitao Liu, Ling Du, Yang Zhong, Е. Ф. Полисадова
Abstract
Cyan-emitting phosphors are important for near-ultraviolet (NUV) light-emitting diodes (LEDs) to gain high-quality white lighting. In the present work, a Bi3+-doped BaScO2F, R+ (R = Na, K, Rb) perovskite, which emits 506 nm cyan-green light under 360 or 415 nm excitation, is obtained via a high-temperature solid-state method for the first time. The obtained perovskite shows improved photoluminescence and thermal stability due to the charge compensation of Na+, K+, and Rb+ co-doping. Its spectral broadening is attributed to two centers Bi (1) and Bi (2), which are caused by the zone-boundary octahedral tilting due to the substitution of Bi3+ for the larger Ba2+. Employing the blend phosphors of Ba0.998ScO2F:0.001Bi3+,0.001K+ and the commercial BAM:Eu2+, YAG:Ce3+, and CaAlSiN3:Eu2+, a full-spectrum white LED device with Ra = 96 and CCT = 4434 K was fabricated with a 360 nm NUV chip. Interestingly, a novel strategy is proposed: the cyan-green Ba0.998ScO2F:0.001Bi3+,0.001K+ and orange Sr3SiO5:Eu2+ phosphors were packaged with a 415 nm NUV chip to produce the white LED with Ra = 85 and CCT = 4811 K.