Mn 4+ -doped fluoride phosphors have been widely used in wide-gamut backlighting devices because of their extremely narrowe mission band. Solid solutions of Na 2 -(Si x Ge 1Àx )F 6 :Mn 4+ and Na 2 (Ge y Ti 1Ày )F 6 :Mn 4+ were successfully synthesized to elucidate the behavior of the zero-phonon line (ZPL) in different structures.The ratio between ZPL and the highest emission intensity u 6 phonon sideband exhibits as trong relationship with luminescent decayr ate.F irstprinciples calculations are conducted to model the variation in the structural and electronic properties of the prepared solid solutions as afunction of the composition. To compensate for the limitations of the Rietveld refinement, electron paramagnetic resonance and high-resolution steady-state emission spectra are used to confirm the diverse local environment for Mn 4+ in the structure.Finally,the spectral luminous efficacy of radiation (LER) is used to reveal the important role of ZPL in practical applications.

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In this study, we present the high pressure spectroscopy of Y3Al2Ga3O12 (YAGG) and Y3Ga5O12 (YGG) ceramics doped with Ce(3+) and Cr(3+). We have found that high hydrostatic pressure recovers the Ce(3+) luminescence in YGG. The pressure-induced shifts of the ground state and the 5d1 excited state of Ce(3+) with respect to the conduction band edge were estimated. Our experimental data allowed us to also obtain the shifts of the conduction and valence band edges, and the ground state and the 5d1 state of Ce(3+) ions have been estimated with respect to the vacuum level. It has been shown that simple equivalence between the external hydrostatic pressure and intrinsic chemical pressure related to different compositions of the isostructural matrices does not exist in garnet lattices.

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