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研究了水热法合成的ZnS:Cu,Tm超细X射线发光粉及其光致发光(PL)和X射线激发发光(X-rayexcited luminescence,XEL)光谱特性.200℃水热处理12h直接合成样品的纳米晶粒径约15nm,尺寸分布窄,分散性好,具有纯立方相的类球形结构.氩气保护下900℃退火1h后的样品存在一定的团聚,但团聚后尺寸为200—600nm,为超细X射线发光粉,此时样品为纯六方相的类球形为主的结构.所有样品的PL和XEL光谱均为宽带谱.水热法直接合成样品的XEL强度最强时,样品的Cu/Zn,Tm/Cu比值分别为3×10-4和2.在此比值条件下,900℃退火1h样品的XEL发光最强,此时其两个峰值分别位于453,525nm.发光强度增强的同时粒径很小,对提高成像系统分辨率非常有意义.通过比较PL光谱与XEL光谱特性,讨论了PL和XEL光谱的发光机理和其不同的激发机理.
The ZnS: Cu, Tm superfine X-ray luminescent powders synthesized by hydrothermal method and their spectral characteristics of photoluminescence (PL) and X-ray emission (XEL) were studied.The samples were directly synthesized by hydrothermal treatment at 200 ℃ for 12h Nanocrystalline particles with a size of about 15nm, narrow size distribution, good dispersibility, pure cubic phase-like spheroidal structure.After argon annealing at 900 ℃ for 1h, there was a certain agglomeration of the sample after agglomeration, but the agglomeration size was 200-600nm, As the ultrafine X-ray luminescent powder, the sample is mainly spherical-like structure of pure hexagonal phase.The spectrum of PL and XEL of all the samples are broad band spectrum.When the XEL intensity of direct synthesis sample by hydrothermal method is the strongest, The ratios of Cu / Zn and Tm / Cu were 3 × 10-4 and 2. Under this ratio, the XEL emission at 900 ℃ for 1 h was the strongest, at which time the two peaks were at 453 and 525 nm, respectively At the same time, the particle size is very small, which is of great significance to improve the resolution of the imaging system.By comparing the PL spectrum with the XEL spectrum, the luminescence mechanism and different excitation mechanism of PL and XEL spectra are discussed.