【作者】 李锦清；

【导师】 孟建新；

【作者基本信息】 暨南大学 ， 分析化学， 2009， 硕士

【摘要】 近红外光具有光穿透深度大,在生物分析中可进行深层组织成像,对被测物质无损害,背景干扰小,灵敏度高等优点,掺杂Er³⁺、Nd³⁺和其它稀土离子的近红外发光材料受到了广泛关注。稀土掺杂无机近红外发光材料的近红外发光强度相对来说还是很弱的,还没有达到免疫分析所要求的发光强度。本文主要从提高近红外发光强度和解决纳米粒子的生物相容性问题进行探讨。具体实验内容有:应用水热法制备了MgWO₄和MgWO₄:Nd³⁺发光材料。研究表明在180℃～230℃,pH=8～10,反应24小时以上可制得纯相且不含结晶水的MgWO₄材料。将水热直接获得的样品在不同温度下煅烧,发现在850℃附近样品四方晶系转变为单斜晶系;随着煅烧温度升高,形貌由片状变为棒状;1050℃煅烧3小时的MgWO₄:Nd³⁺的发光最强;同时发现存在WO^4-对Nd³⁺的能量传递。应用共沉淀法制备了YAG:Ce³⁺,Nd³⁺近红外发光粉末。发现Ce³⁺对Nd³⁺的近红外发光存在高效敏化。用470nm光激发时,Ce³⁺使Nd³⁺的近红外发光强度提高了55倍。分析了Ce³⁺对Nd³⁺的能量传递机理;研究了煅烧温度、掺杂浓度对近红外发光的影响,发现在1500℃煅烧4小时的Ce³⁺掺杂量为5～6%、Nd³⁺掺杂量为5%的样品近红外发光最强。应用高温固相法制备了Sr₂SiO₄:Eu²⁺,Nd³⁺近红外发光粉末。研究了煅烧温度、Eu²⁺的掺杂浓度对Sr₂SiO₄:Eu²⁺发光性质的影响。发现随着煅烧温度升高、Eu²⁺的掺杂浓度增大,Sr₂SiO₄:Eu²⁺的发射峰中心红移。通过对Sr₂SiO₄:Eu²⁺和Sr₂SiO₄:Eu²⁺,Nd³⁺的发光性质以及荧光寿命的研究,证实Sr₂SiO₄基质中存在Eu²⁺对Nd³⁺的能量传递,提高了Nd³⁺的近红外发光强度。探讨了Eu²⁺对Nd³⁺的能量传递机理。利用水热微乳液法制备了CaWO₄:Eu³⁺纳米粒子,研究了水热温度、水热反应时间、反应的pH以及原料起始浓度对CaWO₄:Eu³⁺纳米粒子形貌的影响。获得了形貌规则、大小均匀的、100nm以内的纳米粒子。研究了TEOS的用量对SiO₂包覆CaWO₄:Eu³⁺厚度的影响,成功包覆上二氧化硅,解决了纳米粒子的生物相容性问题。更多还原

【Abstract】 Recently,doped Er³⁺,Nd³⁺ and other rare earth ions of near infrared luminescent materials have been received extensive attention,due to the near-infrared light having many advantages of strong penetrability,deep tissue imaging,having no harm to the tested substances,free of background and high sensitivity in biological analysis.The near infrared luminescent intensity of inorganic materials doped rare earth ions is still weak,has not yet reached the immunoassay requirement.In this paper,the intentions are to improve the strength of near-infrared luminescent intensity and resolve the biocompatibility of nanoparticles.The conclusions and results were summarized as follows:MgWO₄ and Nd³⁺doped MgWO₄ powders were prepared by hydrothermal method.Studies showed that a pure phase of MgWO₄ crystal without crystalline H₂O can be synthesized at 180～230℃of hydrothermal temperature,8～10 of pH value and more than 24-hour of hydrothermal time.The as-prepared has a tetragonal structure and transfer to monocline structure when sintered at 850℃or higher temperature.With the calcination temperature increase,the flake shape samples changed to well dispersed Rod-like particles and an optimized sintering condition is 1050℃for 3 hours.Energy transfer from WO₄^2- group to Nd³⁺ ions was found.YAG:Ce³⁺,Nd³⁺powders were prepared by co-precipitation method.It was found near-infrared luminescence of Nd³⁺ in YAG could be very efficient sensitized with co-doped Ce³⁺, and the NIR emission intensity is almost 55 times of that of YAG:Nd³⁺when excited with a 470nm of an argon laser.The energy transfer mechanism from Ce³⁺ to Nd³⁺ was proposed.The influences of sintered temperature and the dopant concentration were investigated,and the strongest NIR emission of YAG:Ce³⁺,Nd³⁺ samples was obtained when sintered at 1500℃for 4h and doped with 5-6%Ce³⁺ and 5%Nd³⁺.Sr₂SiO₄:Eu²⁺,Nd³⁺samples were synthesized by a solid state method.The effects of sintering temperature,Eu²⁺-concentration on the Sr₂SiO₄:Eu²⁺ luminescence properties were investigated and found that the emission center red-shift with the increase of sintering temperature and Eu²⁺-concentration.It was found that energy transfer from Eu²⁺ to Nd³⁺ in Sr₂SiO₄:Eu²⁺,Nd³⁺ samples,and that mechanism was discussed simply.CaWO₄:Eu³⁺ nanoparticles were synthesized via hydrothermal micro-emulsion.The effects of hydrothermal temperature,hydrothermal time,initial pH and concentration of reactants on the CaWO₄:Eu³⁺ morphology and size were investigated.The uniform morphology and moderate grain size within 100nm particles were attained under the optimum reaction conditions.The core shell structure of CaWO₄:Eu³⁺/SiO₂ were attained for resolving the biocompatibility and made it has the potential application to fluorescence immunoassay.更多还原