本文選題：碳點(diǎn) + 調(diào)控�。� 參考：《西南大學(xué)》2015年碩士論文

【摘要】：自2004年,Xu等首次發(fā)現(xiàn)了熒光碳點(diǎn)后,它成為了繼富勒烯、碳納米管及石墨烯之后最熱門(mén)的碳納米材料之一,引起了人們的廣泛關(guān)注。碳點(diǎn)具有熒光強(qiáng)度高、耐光漂白、無(wú)光閃爍現(xiàn)象、發(fā)射波長(zhǎng)可調(diào)控等優(yōu)良熒光性能,同時(shí)又有生物相容性好、毒性低、原料易得、制備方法簡(jiǎn)便等優(yōu)點(diǎn)。基于這些優(yōu)點(diǎn),碳點(diǎn)有望取代量子點(diǎn)進(jìn)行生物成像,可作為一種可觀察性和可追蹤性的新型的藥物載體,也可設(shè)計(jì)探針檢測(cè)金屬離子、陰離子、有機(jī)小分子及生物分子。此外,碳點(diǎn)因?yàn)閮?yōu)異的物理化學(xué)性能(如光誘導(dǎo)電子轉(zhuǎn)移、氧化還原性),在光催化劑這一領(lǐng)域有很好的應(yīng)用前景以及應(yīng)用于發(fā)光材料,如激光、LED、熒光油墨等。盡管碳點(diǎn)有很多的優(yōu)點(diǎn)和研究應(yīng)用,但是碳點(diǎn)的單顆粒熒光比量子點(diǎn)的弱；碳點(diǎn)的發(fā)射波長(zhǎng)主要集中在藍(lán)光和綠光區(qū)域。盡管有文獻(xiàn)報(bào)道,大多數(shù)碳點(diǎn)的發(fā)射隨激發(fā)的變化而變化,即激發(fā)依賴(lài)型。但是當(dāng)激發(fā)波長(zhǎng)偏離最佳激發(fā)態(tài)較多時(shí)熒光強(qiáng)度很弱。總之,碳點(diǎn)的熒光性能還不能和量子點(diǎn)相比,這成了限制碳點(diǎn)應(yīng)用的瓶頸。因此,調(diào)控碳點(diǎn)的熒光性能是非常必要且迫切的。本文就主要對(duì)調(diào)控和研究碳點(diǎn)的熒光性能做了以下研究：(1)分別以NaBH4和LiAlH4作為還原劑還原油煙碳點(diǎn),得到還原程度不同的兩種碳點(diǎn),分別記為r-CDs1和r-CDs2,成功的調(diào)控了碳點(diǎn)的激發(fā)、發(fā)射和熒光量子產(chǎn)率。而且經(jīng)過(guò)還原處理后,原先某些性能差的碳點(diǎn)可進(jìn)一步生長(zhǎng)為性能較好的碳點(diǎn)。并經(jīng)實(shí)驗(yàn)證實(shí),碳點(diǎn)熒光性能的改變與粒徑無(wú)關(guān),而與表面基團(tuán)的改變有關(guān)。同時(shí),我們還通過(guò)計(jì)算能隙和第一激發(fā)能解釋了還原反應(yīng)調(diào)控發(fā)射波長(zhǎng)的機(jī)制。本工作為調(diào)控碳點(diǎn)的熒光性能、設(shè)計(jì)納米熒光探針提供了新思路。(2)納米金由于在紫外-可見(jiàn)光區(qū)域內(nèi)具有較寬的吸收范圍和較大的吸收系數(shù),這使得它有顯著的猝滅效果,是一種很好的熒光猝滅劑。而碳點(diǎn)的熒光能被多種熒光猝滅劑所猝滅,基于此,我們首次研究了納米金作為一種熒光猝滅劑對(duì)碳點(diǎn)熒光的猝滅行為�？疾炝颂键c(diǎn)濃度、pH值、反應(yīng)溫度和時(shí)間等多種因素對(duì)熒光猝滅的影響,在最佳實(shí)驗(yàn)條件下猝滅常數(shù)為9.1×108 L mol-1。此外,因?yàn)榧尤脞鐒┘{米金前后碳點(diǎn)的熒光壽命基本不變；且隨溫度升高,猝滅常數(shù)減小。因此,推測(cè)納米金對(duì)碳點(diǎn)的熒光猝滅為靜態(tài)猝滅。
[Abstract]:Since Xu et al discovered the fluorescent carbon point for the first time in 2004, it has become one of the most popular carbon nanomaterials after fullerene, carbon nanotubes and graphene. Carbon spots have the advantages of high fluorescence intensity, high photobleaching resistance, no light scintillation, adjustable emission wavelength, good biocompatibility, low toxicity, easy to obtain raw materials and simple preparation methods. Based on these advantages, carbon dots are expected to replace quantum dots for biological imaging, which can be used as a new drug carrier with observability and traceability, and can also be designed to detect metal ions, anions, organic small molecules and biomolecules. In addition, because of its excellent physical and chemical properties (such as photoinduced electron transfer, redox), carbon has a good application prospect in the field of photocatalyst, and can be used in luminescent materials such as laser photoresist, fluorescent ink and so on. Although carbon dots have many advantages and applications, the single particle fluorescence of carbon dots is weaker than that of quantum dots, and the emission wavelengths of carbon dots are mainly concentrated in the region of blue and green light. Although it has been reported that the emission of most carbon points varies with the excitation, that is, the excitation dependent type. However, the fluorescence intensity is very weak when the excitation wavelength deviates from the optimal excited state. In a word, the fluorescence properties of carbon dots can not be compared with those of quantum dots, which has become the bottleneck limiting the application of carbon dots. Therefore, it is very necessary and urgent to regulate the fluorescence properties of carbon points. In this paper, the fluorescence properties of carbon points were studied as follows: (1) reducing oil fume carbon points with NaBH4 and LiAlH4 as reductants, two carbon spots with different reduction degree were obtained, which were recorded as r-CDS1 and r-CDs2 respectively, which successfully regulated the excitation of carbon points. Emission and fluorescence quantum yields. After reduction, some poor carbon points can be further grown into better carbon points. The experimental results show that the change of the fluorescence properties of carbon points is independent of the particle size, but related to the change of the surface groups. At the same time, we calculate the energy gap and the first excitation energy to explain the mechanism of controlling the emission wavelength of the reduction reaction. This work provides a new idea for controlling the fluorescence properties of carbon spots and designing nanoscale fluorescence probes. (2) because of its wide absorption range and large absorption coefficient in the UV-visible region, the nano-gold has a remarkable quenching effect. It is a good fluorescence quenching agent. The fluorescence of carbon point can be quenched by a variety of fluorescence quenching agents. Based on this, we have studied the quenching of carbon point fluorescence by nano-gold as a fluorescence quenching agent for the first time. The effects of pH, reaction temperature and time on fluorescence quenching were investigated. The quenching constant was 9.1 脳 10 ~ 8 L mol ~ (-1) under the optimum experimental conditions. In addition, the fluorescence lifetime of carbon point is almost unchanged before and after the addition of the quencher, and the quenching constant decreases with the increase of temperature. Therefore, it is inferred that the fluorescence quenching of carbon point by gold nanoparticles is static quenching.
【學(xué)位授予單位】：西南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ127.11;TB383.1

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相關(guān)期刊論文 前1條

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本文編號(hào)：2069087