中文摘要：

采用水热法低温（200℃）处理12h直接制备ZnS∶Cu,Al纳米晶,并探讨其光致（PL）和X射线激发（XEL）光谱特性及后续退火处理的影响.XRD和TEM分析表明,水热法直接制备的ZnS∶Cu,Al粒径约为15nm,尺寸分布窄,分散性好,具有纯立方相的球形结构.其PL和XEL光谱均为宽带谱,n（Cu）/n（Zn）=3×10-4和n（Cu）/n（Al）=0.5时PL和XEL光谱强度最大,XEL峰值在470nm处.在此条件下,水热处理3h直接合成的纳米晶在氩气保护下于800℃退火1h后样品的XEL发光进一步增强.XEL光谱强度约是退火前样品的8倍,此时峰值波长在520nm,团聚形成径为200～500nm的类球形六方相结构.发光强度增强,但粒径很小,对提高成像系统分辨率非常有意义.通过比较样品的XEL和PL光谱,讨论了XEL和PL光谱的发光机理和激发机制及退火对其特性的影响.

英文摘要：

ZnS∶Cu,Al nanocrystals were hydrothermally prepared at 200℃and their photoluminescence（PL） and X-ray excited luminescence（XEL） properties were investigated.The effect of further annealing was also studied in detail.The average gain size of the samples with n（Cu） /n（Zn） =3×10-4 and n（Cu） /n（Al） =2,which was directly hydrothermal-treated at 200℃for 12 h,is about 15 nm;the spherical-like nanocrystals with well dispersity and narrow gain size distribution show cubic structure.The PL and XEL spectra of all of the samples show a broad emission band.The maximum PL and XEL intensities are observed for sample with n（Cu） /n（Zn） =3×10-4 and n（Cu） /n（Al） =0.5.The XEL peak center is at about 470 nm. In this condition,the XEL intensity of the sample which was hydrothermally treated at 200℃for 3 h then annealed in Ar at 800℃for 1 h is enhanced and the peak is located at 520 nm.In the meantime,the XEL intensity is about eight times by comparison with that of the samples without annealing.The particles′ agglomerate size is about 200—500 nm and roughly spherical particles show pure hexagonal structure.The samples with highly luminescence efficiencies and the smaller size could enhance the resolution of imaging systems.By comparing the PL and XEL spectra,the luminescence mechanism and different excitation mechanism of PL and XEL and effect of annealing on XEL were also discussed.