Bismuth‐activated, narrow‐band, cyan garnet phosphor Ca3Y2Ge3O12:Bi3+ for near‐ultraviolet‐pumped white LED application

Abstract

AbstractHerein, a novel Bi3+‐activated Ca3Y2Ge3O12 (CYGO) narrow‐band cyan‐emitting phosphor was synthesized. It can be excited from 320–420 nm, and the strongest excitation peak is located at 370 nm, which is suitable for current near‐ultraviolet (NUV) chips perfectly. The full width at half maximum is at 52 nm. By analyzing the crystal structure of the sample, we infer that the Bi3+ ions replace the Y3+ site to form a highly symmetrical BiO6 octahedron. The time‐resolved photoluminescence (TRPL) spectra of CYGO: Bi3+ reveal that the only a single emission center exists in the host lattice. A warm white light–emitting diode (WLED) device with a low correlated color temperature (3148 K) and a high color rendering index (90.2) was fabricated by using the as‐prepared sample, and the significant thermal stability of CYGO: Bi3+ guarantees its potential application in WLEDs. It is verified that the structure with only one crystallographic Y site for Bi3+ dopant occupation and highly symmetrical and dense structure is conducive to realize narrow‐band emission, which will provide experience for researchers to explore more Bi3+‐activated phosphors used for high‐end lighting.