Cr3+ assisted energy transfer for Mn2+ doped zinc gallogermanate with narrow and bright green emission

[Display omitted] •Hydrothermally synthesized zinc gallogermanate (ZGG) nanoflakes.•Tunable emission in nanostructured ZGG by dopant engineering.•Cr3 + induced bright green emission in ZGG:Mn2 + nanoflakes.•Cr3 + acts as a bridge to efficiently transfer the ZGG host emission to Mn2 + ion.•Efficacy of energy transfer is validated by concentration-dependent PL and lifetime. The objective of this work is to obtain bright green and tunable emission by dopant engineering. It has been achieved in zinc gallogermanate (ZGG) nanodiscs by utilizing Mn2+ and Cr3+ ions as dopant and co-dopant, respectively. Based on photoluminescence measurement, we have found that the Cr3+ co-dopant triggers bright green emission of Mn2+ dopant in the nanodiscs by acting as a bridge to efficiently transfer the emission from the ZGG host to Mn2+ ion. We have validated the efficacy of energy transfer by concentration dependent photoluminescence and lifetime measurement. There are only a few reports on green emitting bulk Mn2+ doped ZGG. This work highlights the strategy of chromium co-doping in enhancing its green emission as a nanostructure, which could be extended to other hosts.