Enhanced near IR downconversion luminescence in Eu3+-Yb3+ co-doped V activated ZnO host: An effort towards efficiency enhancement in Si-Solar cells

We report a new V activated ZnO host co-doped with Yb3+ and Eu3+ downconversion (DC) phosphor to convert the UV photons to near Infra-red (NIR) photons. The absorption efficiency of the ZnO host with activator Yb3+ is found to get significantly enhanced with V doping. The NIR emission at 980 nm of Yb3+ is enhanced at an optimal concentration of 3 mol% V in ZnO host (ZV). Further, with an additional sensitizer Eu3+, enhanced NIR emission is observed at 980 nm for the corresponding excitation of Eu3+. The mechanisms for the energy transfer from the host (ZV) and sensitizer (Eu3+) to the activator (Yb3+) are discussed in detail. This enables ZV:Eu3+,Yb3+ as an efficient DC phosphor which could enhance the spectral response of Si-solar cells in the UV range.