Eu~(3+)掺杂浓度及基质氧空位对Ca~(2-x)Eu_xSnO_4发光性能的影响

采用高温固相法制备Ca_(2-x)SnO_4:xEu~(3+)(x=0,0.001,0.005,0.01,0.015,0.02)发光材料,分别在空气和真空氛围中进行烧结,研究Eu3+掺杂浓度及基质中氧空位对样品发光性能的影响。随着Eu~(3+)离子浓度的增加,发射强度呈逐渐增大的趋势,主发射峰由两个分别位于614 nm和618 nm的峰逐步合为一个位于616nm的发射峰。在Ca_(2-x)SnO_4∶xEu~(3+)样品的激发光谱中,存在着200~295 nm的Eu~(3+)-O~(2-)电荷迁移带,随着Eu~(3+)离子浓度的增加,电荷迁移带的峰位由271 nm红移到286 nm。此外,在Eu~(3+)离子掺杂浓度相同的情况下,真空中烧结得到样品的发光强度是空气中烧结得到样品的2倍。这是由于在真空氛围中烧结产生的氧空位增加使得传导电子密度升高,导致发光强度增加。而且,氧空位的增加导致电子陷阱的增多,这使得Ca_(2-x)SnO_4∶xEu~(3+)样品的余辉性能得到了很大程度的提高。

Effects of Eu3+-doped Concentration and Matricial Oxygen Vacancies on The Luminescence Properties of Ca2-xEuxSnO4

Ca2-xSnO4∶xEu3+(x=0, 0. 001, 0. 005, 0. 01, 0. 015, 0. 02)phosphors were prepared by solid-state reaction method in air and vacuum atmosphere, respectively. The influence of Eu3+-doped concentration and oxygen vacancies on the luminescence properties were investigated. With the increas-ing of Eu3+ concentration, the emission intensity increases and the two main emission peaks at 614 nm and 618 nm gradually become one at about 616 nm. In the excitation spectra of Ca2-x SnO4∶xEu3+, the band between 200 nm and 295 nm is charge transfer band of Eu3+-O2-. The peak of charge transfer band moves from 271 nm to 286 nm with increasing Eu3+ concentration. In addition, under the same concen-tration of Eu3+, the luminescence intensity of samples sintered in vacuum is twice as much as that in air. Because the oxygen vacancies increase in the samples sintered in vacuum atmosphere, the conduction electron density rises, which leads to the higher emission intensity. Furthermore, the increase of electron trap leads to the improvement of afterglow properties of Ca2-x SnO4∶xEu3+.