Sol–gel synthesis, characterization and study of substitution effects in different gallium-containing garnets

Gallium-containing garnets (gadolinium gallium Gd 3 Ga 5 O 12 ; GGG, and gadolinium scandium gallium Gd 3 Sc 2 Ga 3 O 12 ; GSGG) were prepared using an aqueous sol–gel synthesis route. Different starting materials and TRIS (tris-(hydroxymethyl)-aminomethane), NH 2 C(CH 2 OH) 3 and 1,2-ethandiol as complexing agents were used in the sol–gel processing. The final products were obtained after the heating of the precursor gels at 1000 °C for 10 h. The substitution effects of Fe 3+ , Ce 3+ , and Ce 3+ /Cr 3+ in gallium garnets have been also investigated. The results obtained in this study have demonstrated that the formation of mixed-metal gallium garnets depends on the sol–gel synthesis parameters and nature of dopant element. The luminescent properties of GGG:Fe 3+ specimens were identical to those of GSGG:Fe 3+ , showing the great iron quenching effect. The luminescence at 720–780 nm for the cerium-/chromium-co-doped GGG:Ce 3+ , Cr 3+ phosphors was observed. The highest emission intensity for GGG:Ce 3+ , Cr 3+ samples containing 3 mol% of dopants (1.5 mol% Ce and 1.5 mol% Cr) was determined. Graphical Abstract Cerium/chromium concentration-dependent luminescence spectra of doped GGG:Ce 3+ , Cr 3+ samples. PL excitation spectrum ( λ em = 730 nm) of pure GGG is presented at left. Emission spectra ( λ ex = 460 nm) of GGG:Ce 3+ , Cr 3+ as a function of Ce 3+ and Cr 3+ concentration are presented at right.