CdTe量子点复合材料的制备及其荧光性能研究
发布时间：2019-06-10 12:57
【摘要】：半导体量子点是一类尺寸小于10nm的纳米晶,由于具有显著的表面效应、量子尺寸效应等而使其具有比传统有机染料更优异的光学特性,在生物标记、离子检测、光电器件等方面应用广泛。水相法合成量子点方法简单,毒性低,更经济。目前利用量子点对金属离子灵敏的荧光猝灭响应,可将其作为离子探针检测水溶液中的金属离子。纯量子点粉体的本征热不稳定性极大的限制了其在固体材料中的应用,本论文采用静电组装法和离子交换原位合成法将CdTe量子点引入层状材料麦羟硅钠石(MD)中,得到性能优异的CdTe/MD复合荧光粉体,进一步通过热熔共混的方法将其与聚乙烯(PE)、聚丙烯(PP)高分子材料复合,得到具有优异荧光特性的高分子复合材料。另外,采用静电纺丝法、原位聚合法,溶剂热蒸发法将合成的CdTe量子点复合到聚甲基丙烯酸甲酯(PMMA)基体中,系统研究了不同工艺条件对CdTe/PMMA复合材料荧光性能的影响。研究结果如下：1.采用水相回流法合成了L-半胱氨酸修饰的CdTe量子点,粒径为2～4nm,可作为荧光探针检测水溶液中的Cu2+浓度,线性范围为400～4000nmol/L,检测限为85nmol/L。对模拟水样中Cu2+的测定值与实际加入值基本吻合。2.采用静电组装法和离子交换原位合成法均能成功将CdTe量子点引入MD层间制备出CdTe/MD复合物荧光粉体。MD层板的限域保护作用有效地抑制了CdTe量子点的团聚,使其在粉体状态仍表现出优异的荧光性能和较好的热稳定性(1)采用静电组装法,当以最大发射波长λem(max)为550nm左右的CdTe量子点为母液,物料比为V(CdTe)/m(MD)=50mL/0.5g时,得到的CdTe/MD复合材料荧光强度最强,其耐热性也最任HRTEM表明CdTe量子点很好地分散于MD基质中,不发生团聚,XRD结果表明量子点的存在不影响MD的主体层板结构。(2)采用离子交换原位合成法,当回流时间为5min-24h,佳复合材料的最大发射波长λem(max)可在501-557nm范围内调谐,当回流时间为30min时,荧光最强。(3)将CdTe/MD复合材料粉体进一步添加到聚乙烯、聚丙烯的热塑中,得到CdTe/MD-PE, CdTe/MD-PP复合材料,材料荧光颜色可在黄色、橙黄色、橙红色间调谐。3.采用静电纺丝法制得CdTe/PMMA复合纤维,其直径为2-3gm,且表面分布有直径为100nm左右的孔,具有与初始量子点溶液基本相同的最大发射波长λem(max)。采用溶剂热蒸发法制备出CdTe含量在2.12～6.10wt%的透明CdTe/PMMA荧光复合薄膜,其中6.1 0 wt%CdTe/PMMA复合物膜的荧光强度最大。TEM表明,CdTe量子点能均匀地分散于PMMA中；荧光分析和荧光寿命测试表明,与纯的量子点粉体相比,PMMA基质中CdTe量子点的荧光性能和光稳定性均有很大的提高。热重分析表明,CdTe量子点的存在对PMMA的热稳定性有所提高。当改变CdTe量子点的最大发射波长λem(max)为539 nm,555 nm,566 nm和588nm时,所制得的6.10wt% CdTe/PMMA复合物膜的最大发射波长λem(max)分别为538,553,565和584 nm,其荧光颜色可在绿色、黄绿色、黄色、橙色间调谐。
[Abstract]:The semiconductor quantum dots are a class of nanocrystals with a size of less than 10 nm. Due to the remarkable surface effect, quantum size effect, and the like, the semiconductor quantum dots have more excellent optical properties than the conventional organic dyes, and are widely applied in the fields of biological labeling, ion detection, photoelectric devices and the like. The method for synthesizing the quantum dots by the water phase method is simple, the toxicity is low, and the method is more economical. At present, the quantum dot is used for the sensitive fluorescence quenching of metal ions, which can be used as the ion probe to detect the metal ions in the aqueous solution. the intrinsic thermal instability of the pure quantum dot powder greatly limits the application of the pure quantum dot powder in the solid material, And the high-molecular composite material with excellent fluorescence property is obtained by compounding the polymer with the polyethylene (PE) and the polypropylene (PP) high-molecular material by a hot-melt blending method. In addition, the effects of different process conditions on the fluorescence properties of the CdTe/ PMMA composite were studied by means of electrospinning, in-situ polymerization, and solvent thermal evaporation. The results of the study are as follows:1. The CdTe quantum dot modified by L-cysteine was synthesized by the aqueous phase reflux method. The particle size was 2-4 nm. The concentration of Cu2 + in the aqueous solution can be detected as a fluorescent probe. The linear range is 400-4000 nmol/ L, and the detection limit is 85 nmol/ L. The measured value of Cu2 + in the simulated water sample is in agreement with the actual addition value. The CdTe/ MD composite phosphor powder can be prepared by introducing the CdTe quantum dots into the MD layer by adopting an electrostatic assembly method and an ion exchange in-situ synthesis method. the limited-domain protection effect of the MD layer effectively inhibits the agglomeration of the CdTe quantum dots so as to exhibit excellent fluorescence performance and better thermal stability in the powder state (1) adopting an electrostatic assembly method, and when the CdTe quantum point with the maximum emission wavelength (max) of about 550 nm is a mother liquid, When the material ratio is V (CdTe)/ m (MD) = 50 mL/ 0.5 g, the obtained CdTe/ MD composite material has the strongest fluorescence intensity, and the heat resistance is also the most HRTEM, which shows that the CdTe quantum dots are well dispersed in the MD matrix without agglomeration, and the XRD results show that the existence of the quantum dots does not affect the structure of the main body of the MD. (2) In situ synthesis with ion exchange, when the reflux time is 5 min to 24 h, the maximum emission wavelength of the good composite material (max) can be tuned in the range of 501-557 nm, and when the reflux time is 30 min, the fluorescence is the strongest. And (3) the CdTe/ MD composite material powder is further added into the thermoplastic of the polyethylene and the polypropylene to obtain the CdTe/ MD-PE and CdTe/ MD-PP composite material, and the fluorescent color of the material can be tuned between yellow, orange and orange. The CdTe/ PMMA composite fiber is prepared by the electrostatic spinning method, the diameter of the CdTe/ PMMA composite fiber is 2-3gm, and a hole with a diameter of about 100 nm is distributed on the surface, and the CdTe/ PMMA composite fiber has the same maximum emission wavelength (max) as that of the initial quantum dot solution. A transparent CdTe/ PMMA fluorescent composite film with a CdTe content of 2.12 to 6.10 wt% is prepared by a solvent thermal evaporation method, wherein the fluorescence intensity of the 6.1wt% CdTe/ PMMA composite film is the largest. TEM shows that the CdTe quantum dots can be uniformly dispersed in PMMA, and the fluorescence analysis and the fluorescence lifetime test show that the fluorescence and photostability of the CdTe quantum dots in the PMMA matrix are greatly improved compared with the pure quantum dot powder. The thermogravimetric analysis shows that the presence of CdTe quantum dots has improved the thermal stability of PMMA. When the maximum emission wavelength (max) of the CdTe quantum dots is changed to 539 nm,555 nm,566 nm and 588 nm, the maximum emission wavelength of the prepared 6.10 wt% CdTe/ PMMA composite film is 538,553,565 and 584 nm, respectively, and the fluorescence color thereof can be tuned between green, yellow, yellow, and orange.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TQ422
本文编号：2496470
[Abstract]:The semiconductor quantum dots are a class of nanocrystals with a size of less than 10 nm. Due to the remarkable surface effect, quantum size effect, and the like, the semiconductor quantum dots have more excellent optical properties than the conventional organic dyes, and are widely applied in the fields of biological labeling, ion detection, photoelectric devices and the like. The method for synthesizing the quantum dots by the water phase method is simple, the toxicity is low, and the method is more economical. At present, the quantum dot is used for the sensitive fluorescence quenching of metal ions, which can be used as the ion probe to detect the metal ions in the aqueous solution. the intrinsic thermal instability of the pure quantum dot powder greatly limits the application of the pure quantum dot powder in the solid material, And the high-molecular composite material with excellent fluorescence property is obtained by compounding the polymer with the polyethylene (PE) and the polypropylene (PP) high-molecular material by a hot-melt blending method. In addition, the effects of different process conditions on the fluorescence properties of the CdTe/ PMMA composite were studied by means of electrospinning, in-situ polymerization, and solvent thermal evaporation. The results of the study are as follows:1. The CdTe quantum dot modified by L-cysteine was synthesized by the aqueous phase reflux method. The particle size was 2-4 nm. The concentration of Cu2 + in the aqueous solution can be detected as a fluorescent probe. The linear range is 400-4000 nmol/ L, and the detection limit is 85 nmol/ L. The measured value of Cu2 + in the simulated water sample is in agreement with the actual addition value. The CdTe/ MD composite phosphor powder can be prepared by introducing the CdTe quantum dots into the MD layer by adopting an electrostatic assembly method and an ion exchange in-situ synthesis method. the limited-domain protection effect of the MD layer effectively inhibits the agglomeration of the CdTe quantum dots so as to exhibit excellent fluorescence performance and better thermal stability in the powder state (1) adopting an electrostatic assembly method, and when the CdTe quantum point with the maximum emission wavelength (max) of about 550 nm is a mother liquid, When the material ratio is V (CdTe)/ m (MD) = 50 mL/ 0.5 g, the obtained CdTe/ MD composite material has the strongest fluorescence intensity, and the heat resistance is also the most HRTEM, which shows that the CdTe quantum dots are well dispersed in the MD matrix without agglomeration, and the XRD results show that the existence of the quantum dots does not affect the structure of the main body of the MD. (2) In situ synthesis with ion exchange, when the reflux time is 5 min to 24 h, the maximum emission wavelength of the good composite material (max) can be tuned in the range of 501-557 nm, and when the reflux time is 30 min, the fluorescence is the strongest. And (3) the CdTe/ MD composite material powder is further added into the thermoplastic of the polyethylene and the polypropylene to obtain the CdTe/ MD-PE and CdTe/ MD-PP composite material, and the fluorescent color of the material can be tuned between yellow, orange and orange. The CdTe/ PMMA composite fiber is prepared by the electrostatic spinning method, the diameter of the CdTe/ PMMA composite fiber is 2-3gm, and a hole with a diameter of about 100 nm is distributed on the surface, and the CdTe/ PMMA composite fiber has the same maximum emission wavelength (max) as that of the initial quantum dot solution. A transparent CdTe/ PMMA fluorescent composite film with a CdTe content of 2.12 to 6.10 wt% is prepared by a solvent thermal evaporation method, wherein the fluorescence intensity of the 6.1wt% CdTe/ PMMA composite film is the largest. TEM shows that the CdTe quantum dots can be uniformly dispersed in PMMA, and the fluorescence analysis and the fluorescence lifetime test show that the fluorescence and photostability of the CdTe quantum dots in the PMMA matrix are greatly improved compared with the pure quantum dot powder. The thermogravimetric analysis shows that the presence of CdTe quantum dots has improved the thermal stability of PMMA. When the maximum emission wavelength (max) of the CdTe quantum dots is changed to 539 nm,555 nm,566 nm and 588 nm, the maximum emission wavelength of the prepared 6.10 wt% CdTe/ PMMA composite film is 538,553,565 and 584 nm, respectively, and the fluorescence color thereof can be tuned between green, yellow, yellow, and orange.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TQ422
【参考文献】
相关期刊论文 前1条
1 张华,徐金锁,唐颐,高滋;层状磷酸锆的合成与性质研究[J];高等学校化学学报;1997年02期
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