Energy transfer processes in Ce3+ and Tb3+ co-doped Ln2Si2O7 (Ln = Y, Gd)

The Ce3+ and Tb3+ co-doped Ln2Si2O7 (Ln = Y, Gd) samples were prepared by sol–gel method. Structure characterization of the phosphor was carried out by X-ray diffraction. The luminescence properties of samples were analyzed by measuring the excitation and emission spectra. It was observed that excitation energy can transfer mutually between Ce3+ and Tb3+ in GPS: Ce3+, Tb3+ samples, while in Y2Si2O7 :Ce3+, Tb3+ samples the energy transfer only progresses from Ce3+ to Tb3+. Based on the energy level diagrams of respective Ce3+, Tb3+ and Gd3+ ion, the detailed pathways for energy transfer are explained.

Research highlights
► The Ce3+ and Tb3+ co-doped Ln2Si2O7 (Ln = Y, Gd) samples were prepared by sol-gel method.
► Energy transfer only conducts from Ce3+ to Tb3+ in Y2Si2O7 host.
► Energy can transfer mutually between Ce3+ and Tb3+ in Gd2Si2O7 host.
► The Tb3+ excitation energy could be transferred to Ce3+ ion via Gd3+ ion as a bridge in Gd2Si2O7 host.
► The Gd2Si2O7 host can convert more VUV and UV radiation into visible light than Y2Si2O7 host.