Time-resolved spectroscopic study of energy transfer in ZnO:EuCl₃ phosphors

EuCl₃-doped ZnO phosphors are synthesized by sintering in vacuum atmosphere. From PL measurements it is found that, with increasing doping concentration, the broad-band emission centered around 530 nm gradually disappears while the sharp red-emission peaks around 620 nm exhibit a pronounced increase. These results, together with XRD, PL excitation spectra and time-resolved spectra measurements, suggest that an energy-transfer process occurs from the self-activated defect center in ZnO host to the Eu³⁺ ion which exists in the host lattice in the form of EuOCl.