ZnO quantum-dot chains codoped with Eu3+ and Er3+ were synthesized by the chemical precipitation method and the codoping effects on the structures, morphologies and optical properties of the powders were briefly investigated. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results indicated the Eu3+ and Er3+ were incorporated into the crystal lattice of ZnO host. Transmission electron microscope (TEM) measurements showed the sizes of the ZnO quantum dots decreased with the increase of Eu3+ and Er3+ doping concentration, and the quantum-dot chains were formed by codoping with Eu3+ and Er3+. The green emissions in the photoluminescence spectra were attributed to 4f-4f of Er3+ inner shell H-2(11/2) -> I-4(15/2) and S-4(3/2) -> I-4(15/2) transitions, and the characteristic red emissions of Eu3+ ions were attributed to the D-5(0) -> F-7(1) and D-5(0) -> F-7(2) transitions, respectively. Moreover, the red emission of the Eu3+ ions gradually decreased with the Er3+ ions doping concentration increased, which may be due to the different energy storage centers in the powders. (C) 2011 Elsevier B. V. All rights reserved.