多功能上转换纳米晶的制备与性能研究

发布时间：2019-04-03 11:25

【摘要】：多功能高效集成化是纳米材料的重要发展方向,目前多功能集成实现手段多集中于异质材料复合,工艺复杂,可靠性低,在单一化合物上实现多功能集成则可以避免这些缺点。上转换纳米材料具有独特的光学特性,可以成为构建多功能纳米系统的理想平台。具备良好上转换发光、磁性能、光热转换性能以及温度传感性能的小尺寸纳米颗粒可同时用于多模成像、温度探针、光热治疗。目前小尺寸单相上转换纳米晶的制备工艺中一些影响因素依旧未得到研究,针对上转换材料的光性能研究较多,光热转换性能与综合的多功能集成研究较少。本文研究了上转换纳米材料制备中成分配比、原料用量、反应温度的影响并且制备了核壳结构,研究了材料的光学性能、温度传感、光热转换性能、多功能集成特性与它们的影响因素。利用热分解法制备了NaYF4:0.2Yb,0.02Er,使用Gd3+取代Y3+有利于六方相的形成与尺寸的降低,NaGdF4:0.2Yb,0.02Er尺寸仅有6.3nm：降低NH4F用量可以增大晶体尺寸：提高OA/ODE可以增大晶体尺寸,并且形貌向棒状转变；提高制备温度有利于六方相形成与提高晶体尺寸。yb3+能明显提高激发光吸收率,yb3+与Er3+的浓度猝灭会降低上转换强度,提高光热转换能力；Na(Y,Gd)F4:Yb,Er纳米晶中随着Gd含量的提高,尺寸不断减小,使表面引起的无辐射跃迁几率提高,因此发光强度不断降低,但光热转化能力增强。包覆惰性壳层进行表面修饰,减少了表面缺陷,可提高发光强度,但降低光热转换,而包覆yb3+含量0.2的活性壳层不仅提高了发光强度,光热转换能力也没有下降。尺寸小于10nm的NaGdF4:Yb,Er同时具有上转换发光、光热转换、温度传感、顺磁性等多重性能,可作为单一纳米颗粒平台,同时实现光学成像、核磁功能成像、温度检测和光热治疗等多功能集成。
[Abstract]:Multi-function and high-efficiency integration is an important development direction of nano-materials. At present, the realization of multi-function integration mostly focuses on heterogeneous material compound, the process is complex and the reliability is low. The realization of multi-function integration on a single compound can avoid these shortcomings. Upconversion nanomaterials have unique optical properties and can be an ideal platform for building multi-functional nanosystems. Small size nanoparticles with good up-conversion luminescence, magnetic properties, photothermal conversion properties and temperature sensing properties can be used in multi-mode imaging, temperature probe and photothermal therapy simultaneously. At present, some factors affecting the preparation of small-size single-phase upconversion nanocrystals have not been studied. There are more studies on the optical properties of up-conversion materials, and less on the integration of photo-thermal conversion performance and comprehensive multi-function integration. In this paper, the effects of composition ratio, amount of raw materials, reaction temperature and core-shell structure on the preparation of upconversion nano-materials were studied. The optical properties, temperature sensing and photothermal conversion properties of the materials were studied. Multi-functional integration characteristics and their influencing factors. The preparation of NaYF4:0.2Yb,0.02Er, by thermal decomposition method using Gd3 instead of Y3 is beneficial to the formation and size reduction of hexagonal phase, NaGdF4:0.2Yb,. The size of 0.02Er is only 6.3 nm: decreasing the amount of NH4F can increase the crystal size; increasing the OA/ODE can increase the crystal size, and the morphology changes to rod shape; Increasing the preparation temperature is beneficial to the formation of hexagonal phase and the increase of crystal size. Byb3 can obviously increase the absorption rate of excited light, and the concentration quenching of yb3 and Er3 can reduce the up-conversion intensity and improve the photothermal conversion ability. The size of Na (Y, Gd) F4Yb, er nanocrystals decreases with the increase of Gd content, which increases the radiative transition probability of the surface. Therefore, the luminescence intensity decreases continuously, but the photothermal conversion ability is enhanced. The surface modification of the inert shell can reduce the surface defect, improve the light intensity, but reduce the photothermal conversion. The active shell coated with yb3 0.2 not only increases the light intensity, but also has no decrease in the photothermal conversion ability. NaGdF4:Yb,Er with size less than 10nm also has multiple properties such as up-conversion luminescence, photothermal conversion, temperature sensing, paramagnetism and so on. It can be used as a single nano-particle platform to realize optical imaging and nuclear magnetic functional imaging at the same time. Multi-functional integration of temperature detection and photothermal therapy.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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