Efficient near-infrared down conversion in Zn2SiO4:Tb3+,Yb3+ thin-films

We demonstrate a facile approach for the synthesis of Zn2SiO4:Tb3+,Yb3+ transparent thin films. The thin film phosphor was characterized by various methods including x-ray diffraction, atom force microscope, and photoluminescence studies. Upon excitation with a UV-blue photon in the range of 350–485 nm, an intense near-infrared (NIR) emission at around 900–1100 nm has been obtained, which is assigned to the electronic transition F27/2→F25/2 of Yb3+ upon exploring the cooperative down conversion mechanism from Tb3+ to Yb3+. The dependence of Yb3+ doping concentration on the visible- and NIR-emissions, decay lifetime, and quantum efficiencies of the thin-films has been investigated. The optimal internal NIR quantum efficiency could be as high as 154.1%.