Optical property and energy transfer in the ZnO-LiYbO <inf>2</inf> hybrid phosphors under the indirect near-UV excitation

The ZnO-LiYbO 2 hybrid phosphors with various Yb 2O 3 and Li 2CO 3 starting concentrations were prepared by using the solid-state reaction method in a weak reducing atmosphere. Under the excitation of ZnO absorption with near-UV photons, the intense near infrared emission originated from Yb 3+: 2+F 5/2 → 2F 7/2 transition can be observed due to the efficient energy transfer from ZnO to Yb 3+ ions. This efficient energy transfer is benefit from the introduction of Yb 3+ ions into ZnO lattice at the interfacial diffusion layers between ZnO and LiYbO 2 crystals. The luminescence decay of Yb 3+ were recorded under the excitation of ZnO intrinsic absorption at 350 nm and excitonic absorption at 395 nm, in which the rise component can be clearly observed and the simulated rise lifetime that describing the population speed are 0.006 and 0.035 ms, respectively. The obvious different population speed of Yb 3+: 2F 5/2 excited level indicates two energy transfer mechanisms from ZnO to Yb 3+: the cooperative energy transfer process under the excitation of intrinsic absorption and the phonon-assistant energy transfer process under the excitation of excitonic absorption, respectively. © 2011 The Electrochemical Society