title: Tuning oxygen vacancy photoluminescence in monoclinic Y2WO6 by selectively occupying yttrium sites using lanthanum.
abstract: The effect of isovalent lanthanum (La) doping on the monoclinic Y2WO6 photoluminescence was studied. Introducing the non-activated La(3+) into Y2WO6 brings new excitation bands from violet to visible regions and strong near-infrared emission, while the bands position and intensity depend on the doping concentration. It is interesting to find that doping La(3+) into Y2WO6 promotes the oxygen vacancy formation according to the first-principle calculation, Raman spectrum, and synchrotron radiation analysis. Through the Rietveld refinement and X-ray photoelectron spectroscopy results, La(3+) is found to mainly occupy the Y2 (2f) site in low-concentration doped samples. With increasing doping concentration, the La(3+) occupation number at the Y3 (4g) site increases faster than those at the Y1 (2e) and Y2 (2f) sites. When La(3+) occupies different Y sites, the localized energy states caused by the oxygen vacancy pair change their position in the forbidden band, inducing the variation of the excitation and emission bands. This research proposes a feasible method to tune the oxygen vacancy emission, eliminating the challenge of precisely controlling the calcination atmosphere.
authors.affiliation: Key Laboratory of Micro-nano Measurement, Manipulation and Physics (Ministry of Education), Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Bangfu
authors.initials: B
authors.lastname: Ding
authors.affiliation: Key Laboratory of Micro-nano Measurement, Manipulation and Physics (Ministry of Education), Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Han
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of high Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lirong
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Micro-nano Measurement, Manipulation and Physics (Ministry of Education), Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Junying
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Rongming
authors.initials: R
authors.lastname: Wang
authors.affiliation: State Key Laboratory of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084, China.
authors.forename: Zilong
authors.initials: Z
authors.lastname: Tang
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