本文關(guān)鍵詞： 表面增強拉曼散射(SERS) 氧化鋅納米梳陣列(ZnO-NC) 銀納米枝狀晶(Ag dendrites) 單鏈DNA(ss-DNA) 金納米顆粒 時域有限差分(FDTD)　出處：《北京化工大學》2016年碩士論文　論文類型：學位論文

【摘要】：拉曼散射是因為光入射到介質(zhì)表面時,由于入射光與分子有互相作用,從而導(dǎo)致的入射光頻率發(fā)生改變的一種散射現(xiàn)象,也叫拉曼效應(yīng)。拉曼散射光譜技術(shù)可以提供很多有用的信息,例如,可以給出分子振動的固有頻率,可以得知分子結(jié)構(gòu)的對稱性信息以及分子內(nèi)部的作用力等等。由于拉曼光譜技術(shù)的一些特點,它常常被稱之為分子的“指紋譜”。但是,在發(fā)展初期,拉曼光譜沒有被廣泛的認識和使用。主要是由于分子的拉曼散射過程非常弱,散射強度不夠。這直接導(dǎo)致物質(zhì)的拉曼信號在實際應(yīng)用的時候達不到靈敏度的要求。因此,表面增強拉曼散射(Surface Enhanced Raman Scattering, SERS)技術(shù)的研究逐漸被人們關(guān)注和重視。SERS技術(shù)是一種高效的光譜檢測技術(shù)。從根本上討論的話,一方面,SERS光譜技術(shù)是由于電磁增強,另一方面是基底表面吸附分子與基底之間的電荷轉(zhuǎn)移構(gòu)成拉曼增強的另一部分活性點,也就是化學增強。這兩者共同構(gòu)成了拉曼光譜的增強原理。SERS增強效果用增強因子(Enhancement factor, EF)來表示,一般可以達到103-107。因此,SERS光譜技術(shù)具有非常高的靈敏度,成為定性以及定量檢測物質(zhì)的又一個有力途徑。SERS光譜技術(shù)由于具備了無損檢測、制樣簡單、快速檢測等優(yōu)點,同時克服了拉曼光譜信號強度低的問題,對于它的應(yīng)用性探究得到了廣泛的關(guān)注,被廣泛應(yīng)用于很多領(lǐng)域。目前,SERS光譜技術(shù)被廣泛用于有毒殘留物質(zhì)的痕量檢測、化學反應(yīng)過程的實時監(jiān)測以及對生物領(lǐng)域的一些分子的定量檢測從而對整個生物反應(yīng)過程進行調(diào)控等等。同時,微納米技術(shù)的發(fā)展為多種形貌的,性能優(yōu)良的SERS基底的制備提供了可能性。目前,主要的研究方向包括：SERS基底結(jié)構(gòu)設(shè)計和制備,SERS基底的性能測試、性能優(yōu)化以及增強機制的討論,基底的功能化修飾、特異性結(jié)合及其應(yīng)用等等。本論文以對某些特定性質(zhì)的有毒有害物質(zhì)分子的痕量檢測、生物分子檢測等為應(yīng)用方向,設(shè)計、制備、表征了幾種高“熱點”密度的微納米結(jié)構(gòu)的SERS基底：硅基氧化鋅納米梳陣列修飾銀納米顆粒基底(ZnO-Nanocomb decorated with Ag nanoparticles, ZnO-NC decorated with AgNPs)、銀納米枝狀晶包裹金膜基底(Ag@Au core-shell dendrites)以及金包銀和殼結(jié)構(gòu)枝狀晶表面修飾單鏈DNA(single-stranded DNA, ss-DNA)的特異性基底。同時設(shè)計了DNA連接金納米顆粒的二聚體結(jié)構(gòu),針對熱點區(qū)域性質(zhì)進行研究,從理論和實驗的對比結(jié)果上來對熱點區(qū)域的SERS性能變化進行探究。論文中,對幾類基底的形貌結(jié)構(gòu)、SERS特性、重復(fù)利用性能、時間穩(wěn)定性、以及多種應(yīng)用性能等方面進行了詳細的測試表征和結(jié)果分析。本論文的具體研究內(nèi)容如下：一、氧化鋅納米梳陣列修飾銀納米顆粒,納米銀枝狀晶包裹金膜以及DNA連接金納米顆粒的二聚體結(jié)構(gòu)的多種基底的制備。以及針對不同的基底的應(yīng)用對基底進行一些表面修飾。首先,制備不同的基底使用了不一樣的實驗方法。這些實驗方法各有優(yōu)劣。對于基底的選擇,應(yīng)該綜合考慮從制備方法、基底結(jié)構(gòu)、到SERS性能等多方面的因素。首先,氧化鋅納米梳陣列修飾銀納米顆�；咨婕暗蕉喾N實驗方法,包括：水熱腐蝕、化學氣相沉積(chemical vapor deposition, CVD)和浸漬還原法,經(jīng)過這一系列的制備過程才能得到最終要使用的基底,綜合來看,該基底的制備實驗方法較為復(fù)雜,消耗時間長。但是,得到的基底具有比較好的規(guī)則結(jié)構(gòu),拉曼測試信號的再現(xiàn)性好,增強性能好；為了簡化實驗過程,設(shè)計了納米銀枝狀晶包裹金膜結(jié)構(gòu)的SERS基底,陣列結(jié)構(gòu)比較規(guī)則,制備過程只涉及到水熱反應(yīng),同時,由于表面包覆了金膜,基底具備了較好的穩(wěn)定性和生物兼容性；最后,為了從理論上解釋“熱點”區(qū)域的SERS性能變化,設(shè)計了DNA連接金納米顆粒的二聚體結(jié)構(gòu),SERS信號分子修飾在熱點區(qū)域不同位置有不同強度的拉曼信號出現(xiàn),組成二聚體的金納米顆粒的直徑尺寸也對SERS信號強度有很大的影響,根據(jù)對實驗結(jié)果的分析,結(jié)合有限時域差分軟件(Finite Difference Time Domain, FDTD)方法,從理論和實驗兩方面互相驗證結(jié)果的可靠性,探究了分子位置,顆粒尺寸等因素對熱點區(qū)域信號強度的影響。二、多種SERS信號分子包括：羅丹明6G(Rhodamine 6G, R6G)、結(jié)晶紫(Crystal violet, CV)以及一些污染物質(zhì)如鎘離子(Cd2+)等作為測試物質(zhì),系統(tǒng)測試并且分析基底的SERS性能、時間穩(wěn)定性、均勻性、重復(fù)利用性、生物兼容性以及待測物的定量關(guān)系曲線等。根據(jù)對表征結(jié)果的系統(tǒng)分析,確定基底的應(yīng)用領(lǐng)域或者針對應(yīng)用前景,對基底進行進一步的修飾或優(yōu)化。三、SERS增強機制的研究。依據(jù)基底的微觀結(jié)構(gòu)特征,采用FDTD模擬的方法對幾種不同結(jié)構(gòu)的基底進行模擬,模擬出隨時間變化基底表面的空間電磁場分布情況。從結(jié)果可見,電磁場增強的區(qū)域即“熱點”(hot spots)是SERS信號來源的主要區(qū)域。為了更進一步的了解熱點區(qū)域的不同位置SERS強度的變化,我們設(shè)計了DNA鏈連接兩個金納米顆粒這一最簡單二聚體結(jié)構(gòu)構(gòu)筑熱點區(qū)域。進一步了解熱點區(qū)域的信號變化有利于我們下一步設(shè)計基底結(jié)構(gòu)以及更加有效地了解間距、尺寸、信號分子的位置等因素對SERS信號的直接影響。
[Abstract]:Raman scattering is because light incident on the surface, due to the incident light and the molecules interact with each other, a scattering of incident light frequency as a result of the change, also called the Raman effect. Technology of Raman spectrum can provide useful information, for example, can give the natural frequency of molecular vibration, the molecular force the structure of information symmetry and molecular internal and so on. Because of some characteristics of Raman spectroscopy, it is often referred to as the molecular "fingerprint". However, in the early stages of development, no Raman spectroscopy to be recognized and widely used. Is mainly due to the Raman scattering process of molecules is very weak, the scattering intensity is not enough. This is a direct result of the Raman signal of material is not up to the requirements of the sensitivity of the actual application of time. Therefore, the surface enhanced Raman scattering (Surface Enhanced Raman Scattering, SERS) technology The research has been gradually paid attention to.SERS technology is a kind of efficient spectrum detection technology. Discussed fundamentally, on the one hand, SERS spectroscopy is due to electromagnetic enhancement, on the other hand is the charge between the molecular adsorption substrate surface and the substrate transfer constitutes another part of active site of Raman enhancement is chemical. Enhanced. The two jointlyform enhancement enhancement factor.SERS enhancement effect principle of Raman spectrum (Enhancement factor, EF) that can reach 103-107. so SERS spectroscopy has very high sensitivity, a qualitative and quantitative detection of material and a powerful way of.SERS spectroscopy with a nondestructive detection system simple, rapid detection etc., and overcomes the problem of low signal intensity of Raman spectrum, to explore its application have attracted much attention and has been widely used In many fields. At present, SERS spectroscopy is widely used for the detection of toxic trace residues, quantitative detection of real-time monitoring of chemical reaction process and some molecules of biological field and the regulation of the biological process and so on. At the same time, the development of micro nanotechnology for various shapes, excellent performance for SERS substrate provides possibility. At present, the main research directions include: SERS basement structure design and preparation, performance test of SERS substrate, discuss the performance optimization and enhancement mechanism, functional modification of the substrate, the specific binding and application and so on. In this paper, some special properties of trace toxic and harmful substances in molecular detection. The detection of biological molecules such as application, design, preparation, SERS substrate micro nano structure characterization of high density "hot spots": Zinc Oxide silicon nano comb array Modified silver nanoparticles (ZnO-Nanocomb decorated with Ag nanoparticles, ZnO-NC decorated with AgNPs), nano silver dendrite wrapped gold substrate (Ag@Au core-shell dendrites) and silver wrapped in gold and shell dendrite surface modified single stranded DNA (single-stranded DNA ss-DNA) the specific substrate. Two dimeric structure is also designed the DNA connection of gold nanoparticles, to research the regional hot property, to explore from the comparison between theoretical and experimental results on variation of SERS performance in hot area. In this paper, the morphology structure of several kinds of substrate SERS characteristics, performance, repeated use of time stability, and a variety of application performance are analyzed and tested characterization and detailed results. The specific contents of this paper are as follows: first, Zinc Oxide nanocombs array modified silver nanoparticles, nano silver dendrite gold film and DNA Poly two connected with the preparation of gold nanoparticles of various substrate structure. And the application of different substrate on the substrate of surface modification. Firstly, the basal system used different experimental methods were not the same. These experimental methods have advantages and disadvantages. For substrate selection, should be considered from the preparation method the basement structure, factors to SERS, performance and other aspects. First of all, Zinc Oxide nanocombs relates to arrays of silver nanoparticles modified substrate to a variety of experimental methods, including hydrothermal corrosion, chemical vapor deposition (chemical vapor, deposition, CVD) and impregnation method, after a series of preparation process to get the substrate. To use the comprehensive view, experiment method of preparing the substrate is complex, long time consumption. However, the rule base has a good structure, Raman test signal reproducibility, performance enhancement Good; in order to simplify the experimental process, the design of SERS base nano silver dendrite inclusion gold membrane structure, array structure comparison rules, preparation process involves the hydrothermal reaction, at the same time, because the surface coating gold film, substrate with good biological compatibility and stability; finally, in order to explain the changes of SERS performance hot spots "in theory, two dimeric structure design of the DNA connection of gold nanoparticles, SERS signal molecule modification in hot regions at different locations with different intensity of Raman signal, consisting of two poly gold nanoparticles of the diameter size has great effect on the signal intensity of SERS, according to the analysis of the experiment the results, combined with the finite difference time domain software (Finite Difference Time Domain, FDTD) method, the reliability from two aspects of theory and experiment results verify each other, to explore the molecular position, particle size and other factors on heat Effect of signal intensity. Two, a variety of SERS signal molecules including: Luo Danming 6G (Rhodamine 6G R6G), crystal violet (Crystal violet, CV) as well as some pollutants such as cadmium ion (Cd2+) as test material, system testing and performance analysis of SERS, the time base stability, uniformity, reuse of biological compatibility and analyte quantitative curves. According to systematic analysis on the characterization results, determine the application base or for application for further modification or optimization of substrate. Three, research on SERS enhancement mechanism. Based on the microstructure characteristics of the substrate, using the FDTD simulation method for several the basement of different structure simulation, simulate the spatial distribution of electromagnetic field changes with time the surface of the substrate. From the results it can be seen that the electromagnetic enhancement region that is the "hot spot" (hot spots) is a SERS signal source The main area. In order to further understand the change of different positions of SERS intensity of regional hot spots, we design a DNA chain connecting two gold nanoparticles the simplest two dimer structure hotspots. To further understand the signal changes of regional hot spots is conducive to our next design of basement structure and more effective understanding of space the size, location and other factors directly affect the signal molecules of SERS signal.

【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：O657.37
，

本文編號：1538236