Local Bi-O bonds correlated with infrared emission properties in triply doped GdYbBiErGaO via temperature-dependent Raman spectra and x-ray absorption fine structure analysis.

A correlation function between the Raman intensities and the nearest-neighbor mean-square relative displacement (MSRD) [Formula: see text] of local Bi-O bonds is successfully established based on x-ray absorption fine structure (XAFS) and temperature-dependent Raman spectra in the temperature range 77-300 K in amorphous and crystalline GdYbBiErGaO. The structural symmetries of GdYbBiErGaO are described by using [Formula: see text] of local Bi-O bonds. More importantly, GdYbBiErGaO is found to show excellent infrared (IR) emission properties due to changes in Bi-O bonds, and the IR emission intensities are found to depend on [Formula: see text], by using temperature-dependent photoluminescence spectroscopy. The maximum emission intensity at 1533 nm is obtained when [Formula: see text] [Formula: see text] at the lowest symmetry. This work shows that temperature-dependent Raman intensities can be used effectively to analyze the local covalent bonds around absorbing atoms as well as to study the emission properties of this visible-light-activated IR luminophor.