title: Enhancing blue luminescence from Ce-doped ZnO nanophosphor by Li doping.
abstract: Undoped ZnO, Ce-doped ZnO, and (Li, Ce)-codoped ZnO nanophosphors were prepared by a sol-gel process. The effects of the additional doping with Li ions on the crystal structure, particle morphology, and luminescence properties of Ce-doped ZnO were investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy and photoluminescence spectroscopy. The results indicate that the obtained samples are single phase, and a nanorod shaped morphology is observed for (Li, Ce)-codoping. Under excitation with 325 nm light, Ce-doped ZnO phosphors show an ultraviolet emission, a green emission, and a blue emission caused by Zn interstitials. The spectrum of the sample codoped with a proper Li concentration features two additional emissions that can be attributed to the Ce(3+) ions. With the increase of the Li doping concentration, the Ce(3+) blue luminescence of (Li, Ce)-codoped ZnO is obviously enhanced, which results not only from the increase of the Ce(3+) ion concentration itself but also from the energy transfer from the ZnO host material to the Ce(3+) ions. This enhancement reaches a maximum at a Li content of 0.02, and then decreases sharply due to the concentration quench. These nanophosphors may promise for application to the visible-light-emitting devices.
  78.55.Et; 81.07.Wx; 81.20.Fw.
authors.affiliation: School of Physical Science and Information Engineering, Liaocheng University, Shandong 252059, People's Republic of China ; Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Shandong 252059, People's Republic of China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shi
authors.affiliation: Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Shandong 252059, People's Republic of China ; School of Materials Science and Engineering, Liaocheng University, Shandong 252059, People's Republic of China.
authors.forename: Changzheng
authors.initials: C
authors.lastname: Wang
authors.affiliation: School of Physical Science and Information Engineering, Liaocheng University, Shandong 252059, People's Republic of China ; Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Shandong 252059, People's Republic of China.
authors.forename: Shuhong
authors.initials: S
authors.lastname: Li
authors.affiliation: School of Physical Science and Information Engineering, Liaocheng University, Shandong 252059, People's Republic of China ; Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Shandong 252059, People's Republic of China.
authors.forename: Qingru
authors.initials: Q
authors.lastname: Wang
authors.affiliation: School of Physical Science and Information Engineering, Liaocheng University, Shandong 252059, People's Republic of China ; Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Shandong 252059, People's Republic of China.
authors.forename: Bingyuan
authors.initials: B
authors.lastname: Zhang
authors.affiliation: School of Physical Science and Information Engineering, Liaocheng University, Shandong 252059, People's Republic of China ; Shandong Provincial Key Laboratory of Optical Communication Science and Technology, Shandong 252059, People's Republic of China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Physics, Beihang University, Beijing 100191, People's Republic of China.
authors.forename: Junying
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Physics and Optoelectronic Engineering, Weifang University, Weifang 261061, People's Republic of China.
authors.forename: Hailing
authors.initials: H
authors.lastname: Zhu
keywords: (Li, Ce)-codoped ZnO; Blue luminescence; Phosphors; Sol-gel