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C31H18N6NiO7, monoclinic, P21/c (no. 14), a = 7.6619(15) Å, b = 18.470(4) Å, c = 19.113(4) Å, β = 90.53(3)°, V = 2704.6(9) Å3, Z = 4, R gt(F) = 0.0608, wR ref(F 2) = 0.1656, T = 293 K.

Achieving the desired color temperature and color rendering index in light sources is challenging because of the deficiency of certain color components, notably cyan in the illumination spectra. In this investigation, we successfully synthesized orthogonal Ca5Ga6O14: Bi3+ (CGO: Bi3+) phosphors with space group Cmc21, featuring two distinct Ca(1) and Ca(2) sites. Under the excitation of 335 nm, a broad cyan emission with a 495 nm peak was observed. Gaussian peak fitting revealed two sub-peaks at 445 and 500 nm, originating from the emission of Bi3+ occupying Ca(1) and Ca(2) sites, respectively. As Bi3+ doping concentration increased, the luminescence experienced a red shift, attributed to the cooperative impact of crystal field splitting and electron cloud rearrangement. Through the substitution of Sr2+ ions, we achieved a 2.15 times enhancement in emission intensity and an increase in lifetime from 0.451 to 0.551 μs. This substitution also led to a consistent increase in the relative emission percentage of Bi(1) from 46.5% to 73.1%, while that of Bi(2) decreased from 70.5% to 44.9%. It is likely a result of some Bi3+ ions originally situated in the Ca(2) site migrating to the Ca(1) site. Finally, the introduction of Na+ ions for charge compensation resulted in a 20.18% increase in the luminescence intensity and an enhanced quantum efficiency of 84.21%. This CGO: Bi3+ phosphor holds promise as a potential cyan phosphor for white light sources. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]