Full-visible-spectrum lighting realized by a novel Eu2+-doped nitride-based cyan-emitting phosphor

Abstract

Cyan phosphors have attracted considerable attention in recent years as an indispensable component for realizing full-spectrum lighting. In this study, a novel nitride-based cyan-emitting phosphor Ca₂BN₂Cl:Eu²⁺ was successfully prepared. Its crystal structure refined by the Rietveld refinement reveals that Ca₂BN₂Cl is formed by a tight host lattice and the edge-sharing Ca(N,Cl)₄ tetrahedrons along with multiple crystallographic Ca sites for Eu²⁺ ions to occupy, which corresponds to its broad emission band. Under the near ultraviolet (NUV) light excitation, Ca₂BN₂Cl:Eu²⁺ emits a broad-band cyan light and its full width at half-maximum (FWHM) can reach 121 nm, which effectively compensates the “cyan cavity”. The time-resolved photoluminescence (TRPL) spectra of Ca₂BN₂Cl:Eu²⁺ were investigated to expose the energy transfer between the multiple luminescent centers. Furthermore, the temperature-dependent spectra of Ca₂BN₂Cl:Eu²⁺ were measured to evaluate its thermal stability. All of the discussion and results reveal that Ca₂BN₂Cl:Eu²⁺ is a promising cyan phosphor for use in white light-emitting diodes to realize full-spectrum lighting.