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

Herein, 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.

Automated summary

A novel narrow-band cyan-emitting phosphor CYGO: Bi3+ was successfully synthesized, showing unique luminescent properties and potential applications in high-end lighting. The WLED device fabricated using this phosphor exhibited low correlated color temperature and high color rendering index, indicating great thermal stability and efficient performance.