ZnS/PVA纳米复合薄膜的制备与表征

Synthesis and Characterization of Zinc Sulfide/Polyvinyl Alcohol Nanocomposite Films

采用提拉真空干燥的方法制备出以石英玻璃为基板的ZnS/PVA纳米复合薄膜。ZnS/PVA纳米复合溶胶是通过直接混合法将ZnS纳米粒子与聚乙烯醇 (PVA)高分子材料水溶液直接混合制备得到。ZnS纳米粒子由微乳液法制备得到。利用透射电子显微镜 (TEM)和X射线衍射 (XRD)分析表征了ZnS纳米粒子的微观形貌和晶型 ,TEM结果表明C12 H2 5SH与Zn2 + 的比例越大 ,ZnS粒子的粒径越小且在PVA中的分散越好 ,当C12 H2 5SH/Zn2 + 的比例为 8∶1时 ,ZnS纳米粒子的粒径为 5 0nm ,呈球状 ;XRD分析表明 ,PVA中ZnS纳米粒子具有类似于立方 β ZnS晶相。用紫外 可见 (UV VIS)吸收光谱和荧光光谱 (PL)对其光学性能进行了表征 ,结果表明随着C12 H2 5SH/Zn2 + 的摩尔比从 4∶1增长到 8∶1,ZnS/PVA纳米复合薄膜的吸收峰的强度逐渐增强 ,峰位也逐渐向短波长方向偏移。在 2 80nm下激发 ,PL中出现了峰位位于 36 5nm处的荧光发射峰 ;并且发现随着C12 H2 5SH/Zn2 + 摩尔比从 2∶1增大到 8∶1,在C12 H2 5SH/Zn2 + 摩尔比为 4∶1时 ,荧光发射峰的强度相对较大 ,其余的荧光发射峰蓝移并且强度增大 ,表现出较为明显的量子尺寸效应 ;当C12 H2 5SH/Zn2 + 摩尔比较大时 ,出现了低能发光 (4 5 0nm～ 4 6 7nm)的现象。

Nano-composite films of zinc sulfide and polyvinyl alcohol (PVA) were grown by dipping (and withdrawing) a quartz plate in ZnS/PVA gel prepared by micro-emulsion method,followed by vacuum drying.The structures and optical properties of the films were characterized with X-ray diffraction (XRD),transmission electron microscopy (TEM),ultraviolet-visible (UV-VIS) absorption spectroscopy and fluorescence spectroscopy (PL).The results show that the molar ratio of C 12 H 25 SH and Zn 2+ significantly affects many factors,including the shape,size and dispersion of the ZnS nano-particles as well as the PL band intensity and its peak position.For instance,as the ratio changes from 4∶1 to 8∶1,the absorption intensity peak increases with an observable blue shift.