本文選題：自組裝納米材料 + 飛秒時間分辨光譜　； 參考：《吉林大學(xué)》2015年碩士論文

【摘要】：伴隨著制備技術(shù)的進步，納米材料科學(xué)的發(fā)展從單純的制備不同形態(tài)的納米材料，拓展到對材料體系的物理特性研究上，重在明晰微觀尺度材料的相關(guān)物理機制。同時，人們努力將微觀尺度下豐富多彩的量子局限效應(yīng)拓展到介觀甚至宏觀領(lǐng)域。現(xiàn)在，通過化學(xué)手段，在超晶格或超分子體系中，這種期待得到實現(xiàn)，相關(guān)的材料研究逐步興起。本文正是基于納米科學(xué)發(fā)展的這兩個重要方面，在微觀尺度研究納米材料物性與量子局限關(guān)系的同時，將量子局限效應(yīng)通過化學(xué)組裝的方法拓展到宏觀，并對拓展之后的材料整合特性進行了研究。具體內(nèi)容如下： 本論文所使用的材料體系為巰基乙酸(thioglycolic acid)鈍化的CdTe(TGA-CdTe)量子點。在強偶極相互作用下，CdTe量子點通過層級自組裝形成超分支納米結(jié)構(gòu)，其結(jié)構(gòu)的構(gòu)建單元為原始CdTe量子點。研究表明：超分支納米結(jié)構(gòu)形態(tài)受熟化時間、環(huán)境pH值以及輔助劑比例的影響；組裝后的結(jié)構(gòu)同時具備介觀尺度和量子局限性兩個特點，同時表現(xiàn)出光學(xué)特性上的整合性能，特別是分枝狀結(jié)構(gòu)已被實驗驗證可具有更好的電荷分離效果，因此該種結(jié)構(gòu)在光伏轉(zhuǎn)換和傳感等領(lǐng)域有著重要的潛在應(yīng)用價值。 主要研究成果如下： 第一部分，通過對合成量子點方法優(yōu)缺點的對比，我們選擇相對環(huán)保，實驗條件溫和的水熱法成功制備高質(zhì)量的TGA-CdTe量子點，并對其形貌和穩(wěn)態(tài)光學(xué)性質(zhì)進行了表征。隨后利用瞬態(tài)吸收和熒光上轉(zhuǎn)換技術(shù)對合成后的TGA-CdTe量子點進行激發(fā)態(tài)弛豫動力學(xué)的探測。我們發(fā)現(xiàn)量子局限效應(yīng)對激發(fā)態(tài)弛豫過程有強烈的影響。 第二部分，通過CdTe量子點自組裝的方式，構(gòu)建了層級型納米超分支結(jié)構(gòu)，并對超分支結(jié)構(gòu)進行了形貌與光學(xué)特性的表征。實驗結(jié)果表明，CdTe在超分支結(jié)構(gòu)上，原始量子點單元被保存下來，即超分支納米結(jié)構(gòu)繼承了原始TGA-CdTe量子點的量子局限效應(yīng)。同時，因為與溶液中單分散的量子點相比，量子點與量子點之間的間隔縮小了很多，因此量子點之間形成比較完善的網(wǎng)絡(luò)連接性，時間分辨實驗證明其有利于載流子的擴散傳輸。 第三部分，我們構(gòu)造了CdTe量子點-Au納米粒子組成的激子-等離子體系，利用時間分辨光譜手段，研究了Au粒子的引入對CdTe量子點體系的激子復(fù)合過程的影響，我們發(fā)現(xiàn)隨著Au納米粒子摻雜比例的增加，體系熒光淬滅效果越明顯。時間分辨實驗清楚的顯示了局域場效應(yīng)是引起這種淬滅的原因。 本論文利用超快時間分辨光譜技術(shù)對合成的TGA-CdTe量子點的激發(fā)態(tài)弛豫過程進行了深入的研究，發(fā)現(xiàn)量子局限效應(yīng)對激發(fā)態(tài)弛豫有強烈的影響，這對改善光電器件的光電轉(zhuǎn)換效率有一定的理論參考價值。另外，我們制備的超分支結(jié)構(gòu)，，比量子點具有更好的電荷分離效果；同時，超分支狀結(jié)構(gòu)能夠提高對太陽光的收集效率，因此該種結(jié)構(gòu)在光伏轉(zhuǎn)換和傳感等領(lǐng)域有著重要的潛在應(yīng)用價值。最后，我們利用時間分辨光譜手段對CdTe量子點-Au納米粒子的二元體系熒光淬滅現(xiàn)象做了分析解釋，為探索二元體系能量轉(zhuǎn)移機理提供實驗依據(jù)。
[Abstract]:With the progress of preparation technology, the development of nanomaterial science has developed from simple preparation of different forms of nanomaterials to the physical properties of the material system, and the physical mechanism of microscale materials is clarifying. At the same time, people strive to extend the rich and colorful quantum confinement effect at microscale to mesoscopic and even macro. Now, this expectation is realized by chemical means in superlattice or supramolecular system, and the related material research is rising gradually. This article is based on the two important aspects of the development of nanoscience. At the same time, the quantum confinement effect is assembled by chemical assembly while studying the relationship between the physical property and the quantum confinement of nanomaterials. The method is extended to the macro level, and the characteristics of material integration after expansion are studied.
The material system used in this paper is a CdTe (TGA-CdTe) quantum dot passivated by mercapto (thioglycolic acid). Under the strong dipole interaction, the CdTe quantum dots pass through the hierarchical self-assembly to form a super branched nanostructure. The structure of the structure is a primitive CdTe quantum dot. The study shows that the morphology of the super branched nanostructure is subjected to the ripening time and the ring. The influence of the pH value and the proportion of the auxiliary agent; the assembled structure has two characteristics of mesoscopic scale and quantum limitation, and also shows the integration performance of optical properties, especially the branching structure has been experimentally verified to have a better charge separation effect. Therefore, the structure has the emphasis in the fields of photovoltaic conversion and sensing. The potential application value.
The main research results are as follows:
In the first part, by comparing the advantages and disadvantages of the synthetic quantum dots, we choose a relatively environmentally friendly and mild hydrothermal method to prepare the high quality TGA-CdTe quantum dots, and characterize their morphology and steady state optical properties. Then the TGA-CdTe quantum dots are made by transient absorption and fluorescence upconversion technology. We find that the quantum confinement effect has a strong effect on the relaxation process of excited states.
In the second part, a hierarchical nano superbranch structure is constructed by means of CdTe quantum dots self-assembly, and the morphology and optical properties of the superbranched structure are characterized. The experimental results show that the original CdTe is preserved in the superbranching structure, that is, the superbranch nanostructures inherit the quantum dots of the original TGA-CdTe quantum dots. At the same time, as compared with the monodisperse quantum dots in the solution, the interval between quantum dots and quantum dots is reduced a lot, so a more perfect network connectivity is formed between the quantum dots, and the time resolution experiment proves that it is beneficial to the carrier diffusion.
In the third part, we constructed the exciton plasma system composed of CdTe quantum dots -Au nanoparticles. Using time resolved spectroscopy, we studied the effect of the introduction of Au particles on the exciton recombination process of the CdTe quantum dots system. We found that the fluorescence quenching effect of the system was more obvious with the increase of the proportion of Au nanoparticles. Time resolution was found. The experiment clearly shows that the local field effect is the cause of this quenching.
In this paper, the excited state relaxation process of the synthesized TGA-CdTe quantum dots is deeply studied by using the ultrafast time resolved spectroscopy. It is found that the quantum confinement effect has a strong influence on the excited state relaxation. This has some theoretical value for improving the photoelectric conversion efficiency of the photoelectric devices. In addition, we have prepared the super branching structure. At the same time, the super branching structure can improve the collection efficiency of the sun light, so the structure has an important potential application value in the field of photovoltaic conversion and sensing. Finally, we use the time resolved spectroscopy to quench the two element system of the CdTe quantum dots -Au nanoparticles. The phenomenon is analyzed and explained to provide experimental evidence for exploring the mechanism of energy transfer in the two element system.

【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O471.1

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