【作者】 付少博；

【导师】 冯威； 罗昔贤；

【作者基本信息】 大连海事大学 ， 环境科学与工程， 2011， 硕士

【摘要】 上转换发光材料是一种应用范围极广的功能材料,其在生物分子的荧光标记、固体激光器、太阳能电池、环境净化等方面均显示出了巨大的潜力和独特的优势。本论文针对其在环境科学领域的独特应用开展了稀土掺杂上转换发光材料的研究工作,制备出了高转换效率的稀土掺杂上转换发光材料β-NaYF4:Yb,Er(/Tm)。该材料的光转换效率高,可有效节约资源和能源,若将其用作荧光标记材料或与Ti02等光催化剂复合联用,则可有效扩展功能材料在环境监测、分析和环境治理方面的应用。论文的主要研究内容如下：(1)利用高温固相反应法分别制备出了不同温度的样品,对不同温度下制备的样品进行了表征和分析,结果发现630℃煅烧3h的样品物相最纯,主要生成β-NaYF4,且发光强度最高；而其它温度下烧制的样品,或含其它杂相,或发光强度不高。(2)利用水热法,研究了不同表面活性剂对样品形貌的影响,对比了其不同的发光性能。在相同的条件下使用EDTA制备的样品形貌最好,使用柠檬酸制备的样品发光强度最高。(3)利用溶剂热法,在水／乙醇／油酸体系中制备的NaYF4:Yb,Er和NaYF4:Yb,Tm样品,与使用高温固相法和水热法制备的样品进行综合对比后,发现使用三种方法通过控制合适的反应条件均可制备出纯相的β-NaYF4,三种方法制备的样品发光强度的大小排序为高温固相法>水热法>溶剂热法。(4)对所制备的Yb-Er共激活体系和Yb-Tm共激活体系的β-NaYF4晶体分别在(绿光区、红光区)和(蓝光区、红光区)的上转换发光机理进行了探讨。通过分析泵浦功率与发光强度的关系发现,Yb-Er共激活体系的绿光和红光发射均属双光子过程,而Yb-Tm共激活体系的发光则兼有双光子、三光子和四光子过程。更多还原

【Abstract】 Upconversion luminescence materials is a kind of functional materials with wide application. They have shown great potential and especial advantages in labeled biological molecules, solid-state lasers, solar cells, environmental purification etc. In this thesis, we carried on the research of rare earth doped upconversion luminescence materials for its unique application in environmental science,,and synthesizedβ-NaYF4 of high conversion efficiency, which can effectively save resources and energy. This materials may apply in environmental monitoring, analysis and pollution control fields as fluorescence labeled material or composited with TiO2.The main contents are as follows:(1)The samples were prepared by high temperature solid-state synthesis at different temperatures, and were characterized and analyzed.lt was found that the sample calcined for 3h at 630℃had the most pure phase, and of which the main product was P-NaYF4 and it had the highest luminescence intensity, while samples at other temperatures contained impure phase and luminescence intensity was not high.(2) The impact of different surfactants on morphology of samples was carried on by hydrothermal synthesis, and different luminescence properties were compared. The results indicated the morphology of sample added EDTA under the same condition was the best and the luminescence intensity of sample added citric acid was the highest.(3)The NaYF4:Yb,Er and NaYF4:Yb,Tm were prepared by solvothermal synthesis in water/ethanol/oleic acid system. The properties of prepared samples were comprehensively compared.It is found that pure phaseβ-NaYF4 can be synthesized by controlling appropriate reaction conditions. The order of luminescence intensity of samples synthesized by three methods from high to low was solid-state synthesis, hydrothermal synthesis and solvothermal synthesis.(4) Upconversion mechanism in green area, red area in P-NaYF4 of Yb-Er co-activate system and it in blue area, red area inβ-NaYF4 of Yb-Tm co-activate system was discussed, respectively. From the analysis of relationship between pumped power and luminescence intensity, we can deduced that green emission and red emission belong two-photon process in Yb-Er co-activate system, while the visible area emission of Yb-Tm co-activate system contains two-photon, three-photon and four-photon process.更多还原