In3+, Si4+共掺杂ZnBi0.02Ga1.98O4∶Cr3+的发光与长余辉性能研究

doi:10.3964/j.issn.1000-0593(2020)12-3716-06

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Abstract Long afterglow materials have broad application prospects in biomedicine, information storage and so on. Materials with blue, green and yellow afterglow in different systems have successfully prepared, and some of them with good long afterglow properties have met the requirements of practical applications. However, the red long afterglow materials are not ideal in terms of their luminosity and afterglow time. In this paper, In³⁺ and Si⁴⁺ co-doped Zn(Bi)Ga₂O₄∶Cr³⁺ materials with deep red light luminescence were prepared by high temperature solid-state reaction through. The properties of the luminescent spectra, long afterglow and thermoluminescence of the as-prepared materials were systematically studied. XRD shows that In³⁺ and Si⁴⁺ ions participate in the solid state reaction and occupy the appropriate lattice position of Zn(Bi)Ga₂O₄, and the co-doped In³⁺ and Si⁴⁺ ions have not changed the structure of the host of ZnGa₂O₄. The excitation spectra of Zn(Bi)Ga₂O₄∶1%Cr³⁺; Zn(Bi)Ga₂O₄∶1%Cr³⁺, 9%In³⁺ and Zn(Bi)Ga₂O₄∶1%Cr³⁺, 9%In³⁺, 7%Si⁴⁺ have been measured by monitoring emission wavelength at 687 nm. The co-doped In³⁺ and Si⁴⁺ ions change the local environment of Cr³⁺, thereby causing the red-shift of the excitation band corresponding to the charge transfer from the 2p orbital of O^2- to the 4s4p orbital of Ga³⁺. Meanwhile, the strength of the 4A²-4T¹ and 4A²-4T² transitions of Cr³⁺ is also significantly enhanced by the In³⁺ and Si⁴⁺ co-doped. From the emission spectra excited by the 440 nm light of xenon lamp, it is found that the introduction of In³⁺ ions changes the local environment of some Cr³⁺ ions in octahedrons, results in the different emission peak positions of Cr³⁺ in different lattice sites. This leads to the inhomogeneous broadening of the luminescence spectra in the In³⁺ doped samples. At the same time, the change of the local environment of Cr³⁺ ions caused by In³⁺ doping also improves the emission intensity of the samples. The In³⁺ and Si⁴⁺ co-doping further enhances the inhomogeneous broadening of the emission spectra and the luminescence intensity is also intensified. It is found that Zn(Bi)Ga₂O₄∶Cr³⁺ co-doped with 9%In³⁺, 7%Si⁴⁺ presents the best photoluminescence properties in our experiment. Based on the measured afterglow decay curves, it is found that the introduction of In³⁺ can greatly improve the afterglow brightness of the sample and prolong the afterglow time. Moreover, the further introduced Si⁴⁺ions can ulteriorly improve the afterglow brightness and prolong the afterglow time. Thermoluminescence tests show that the introduction of In³⁺ ions can increase the depth of trap levels in the sample, while the co-doped In³⁺, Si⁴⁺ ions with appropriate concentrations not only increase the depth of the trap but also enhance the concentration of traps in the sample. The investigation in the present work proves that Zn(Bi)Ga₂O₄∶Cr³⁺ co-doped with 9%In³⁺, 3%Si⁴⁺ have the best long afterglow properties. Related studies provide a meaningful reference for further optimization of long afterglow gallate materials.

Key words：ZnBi_0.02Ga_1.98O₄∶Cr³⁺; In-Si co-doped; Fluorescence; Long afterglow

Received: 2019-11-02 Accepted: 2020-03-09

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TB34

Corresponding Authors: XIAO Si-guo E-mail: xiaosiguo@xtu.edu.cn

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http://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2020)12-3716-06 OR http://www.gpxygpfx.com/EN/Y2020/V40/I12/3716