ABSTRACT LiGa 5‐x (YbRCr) x O 8 (R = Ho, Er) ceramics were synthesized via the solid‐state reaction method. Rietveld fitted X‐ray diffraction (XRD) patterns conveyed an increase in the lattice parameters and tensile strain in the co‐doped samples. The UV‐visible absorption spectra revealed decreased band gap energy and additional near‐infrared (NIR) absorption in the Yb co‐doped samples. Down‐conversion photoluminescence (PL) spectroscopy, with 275 nm excitation, showed strong red emission characteristics. The up‐conversion PL, under 980 nm excitation, showed prominent green and red emissions for Yb 3 + /Ho 3 + and Yb 3 + /Er 3 + co‐doping combinations, respectively. The mechanism of up‐conversion PL was explained by energy transfer processes among Cr 3 + , Yb 3 + , Er 3 + , and Ho 3 + ions. Colorimetric analysis showed a red emission in co‐doped samples. These results highlight the potential of LiGa 5 O 8 ‐based phosphors for photonic and energy conversion technologies.
Kumar et al. (Sun,) studied this question.