Strong luminescence and efficient energy transfer in Eu3+/Tb3+-codoped ZnO nanocrystals

Abstract Single crystalline Eu3+/Tb3+-codoped ZnO nanocrystals have been synthesized by using a simple co-precipitation method. Successful doping is realized so that strong green and red luminescence can be efficiently excited by ultraviolet and near ultraviolet radiation, demonstrating an efficient energy transfer from ZnO host to rare earth ions. The energy transfer from the ZnO host to Tb3+ in ZnO: Tb3+ samples and ZnO host to Eu3+ in the ZnO: Eu3+ samples under UV excitation are investigated. It is found that the red 5D0 → 7F2 emission of Eu3+ ions decreases with increasing temperature but the green 5D4 → 7F5 emission of Tb3+ ions increases with increasing temperature, implying a different energy transfer processes in the two samples. Moreover, energy transfer from Tb3+ ions to Eu3+ ions in ZnO nanocrystals is also observed by analyzing luminescence spectra and the decay curves. By adjusting the doping concentration, the Eu3+/Tb3+-codoped ZnO phosphors emit green and red luminescence with chromaticity coordinates near white light region, high color purity and high intensity, indicating that they are promising light-conversion materials and have potential in field emission display devices and liquid crystal display backlights.