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水热法及微乳液法制备无机发光材料

Hydrothermal Method and Microemulsion Method Synthesis of Inorganic Luminescent Materials

【作者】 刘俊

【导师】 马峻峰;

【作者基本信息】 中国海洋大学 , 材料物理与化学, 2008, 硕士

【摘要】 无机发光材料广泛的应用于照明设备、彩色电视荧光屏和大屏幕彩色显示板、电脑显示器、X射线增感屏、X射线断层扫描医疗诊断技术和荧光免疫监测分析技术等诸多方面。目前实际应用与研究最为广泛的发光材料主要有硫化物、钼酸盐。在材料的制备研究中,对粉体的形貌和尺寸的可控合成一直是研究的热点。因此,寻找简单温和、易操作的方法,实现对各种无机发光材料的形貌、尺寸的可控合成是本论文的主要创新点,基于这个创新点,本文主要介绍了水热法和微乳液法两种方法,进行了如下几个方面的主要研究:(一)以硝酸铋(Bi(NO33.5H2O)和硫脲(NH4SCN)为原料,采用LiOH作为矿化剂,低温水热合成了具有纤维状的硫化铋微晶材料,并利用XRD、SEM、PL等分析技术对粉体矿相组成、微观形貌和发光性能进行了表征。详细研究了反应时间、反应温度和矿化剂的引入对硫化铋微晶形成的影响;研究表明,不添加任何矿化剂直接水热反应只能得到不规则的团聚块体硫化铋微晶材料;而以LiOH作为矿化剂水热反应,比较容易得到纤维状的硫化铋微晶。在一定的范围内提高水热反应温度有利于硫化铋微晶的定向生长。另外,荧光光谱分析表明硫化铋粉体的发光性能与其结晶形貌有关。(二)以硝酸锌(Zn(NO32·6H2O)和硫化钠(NaS·9H2O)为原料,采用微乳液法制备前驱体,在160℃低温水热合成了5–10nm的硫化锌纳米粉体并利用XRD、SEM、PL等分析技术对粉体矿相组成、微观形貌和发光性能进行了表征。研究结果表明,提高水热反应温度或延长水热反应时间均有利于硫化锌的结晶发育,提高水热反应温度的影响效果更为明显。硫化锌纳米粉体的发光性能明显优于微米粉体,并且发光中心发生了明显的蓝移。(三)以氯化锶(SrCl2·6 H2O)和钼酸钠(Na2MoO4·2H2O)为原料,选定环己烷为油相, OP(聚氧乙烯壬基苯酚醚)为表面活性剂,正戊醇为助表面活性剂,采用反相微乳液法在室温下成功地制备了不同结晶形貌的SrMoO4粉体,并利用XRD、TEM、SEM、PL等分析测试技术对粉体进行了表征。研究结果表明,在相同的微乳体系下静置不同的反应时间可以得到不同形貌的粉体颗粒。荧光光谱分析表明,钼酸锶粉体的发光性能与其形貌和长径比有关。

【Abstract】 Inorganic luminescent materials have attracted much attention due to their extensive application in many different technological areas, including biological labeling and diagnostics, light emitting diodes, photoconductive devices, optical waveguide, and lasers. At present, sulfide semiconductor and metal molybdate materials have received much attention owing to their wide application potential in many fields. Study on the size- and morphology-control synthesis is still a challenge. The development and synthesis of inorganic luminescent materials were introduced in the thesis, mainly discussing the synthesis methods such as Hydrothermal and microemulsion methods.(一)Uniform Bi2S3 fibers were synthesized via a template-free hydrothermal route using bismuth nitrate (Bi(NO3)3·5H2O), thiourea (CS(NH2)2) and lithium hydroxide (LiOH) as starting materials. The resultant powders were characterized in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescent spectra techniques (PL), respectively. It was found that Bi2S3 fibers could be easily synthesized in the presence of LiOH, whereas only irregular and aggregated particles were obtained without adding LiOH; and that elevating hydrothermal reaction temperature in a certain range would promote the preferred orientation growth of Bi2S3 crystallites. The PL spectra results evidenced that the optical properties of Bi2S3 crystallites were obviously influenced by their size and morphology.(二)Uniform and spherical ZnS nanoparticles with a diameter of 5–10 nm were successfully synthesized at 160℃via a facile hydrothermal process, where ZnS precursors were prepared by a microemulsion technique. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescent spectra techniques (PL), respectively. The results showed that the hydrothermal temperature exerted a more important effect than the holding time on the crystallization of ZnS crystallites. The as-prepared ZnS nanoparticles exhibited higher PL intensity than that of the normal ones of micrometer scale besides an obvious blue shift.(三)SrMoO4 crystallites with varying morphology have been prepared by the chemical reaction of Strontium chloride and Sodium molybdate in a reverse microemulsion system consisting of water, OP (P-octyl polyethylene glycol phenylether, non-ionic surfactant), 1-pentanol (co-surfactant) and cyclohexane (oil). The resultant powders were characterized in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and photoluminescent spectra techniques (PL), respectively. It was found that SrMoO4 crystallites with different morphologies could be synthesized by the microemulsion process with different aging times. The PL spectra results showed that the spindle-shape SrMoO4 crystallites with a higher aspect ratio resulted in better photoluminescence property.

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