【作者】 周林；

【导师】 胡悦；

【作者基本信息】 温州大学 ， 化学， 2021， 硕士

【摘要】 表面增强拉曼散射（SERS）作为检测、鉴定和分析的强有力手段,发现之初就被认为是最具实际应用潜力的表面分析手段之一,现已广泛用于分子结构识别、生物领域分析和医学检测。而贵金属在SERS领域里占着举足轻重的地位,研究表明高度多孔、粗糙的金属表面具有明显的SERS效应,且SERS活性与基底的材料、特征尺寸等都有关联,而基底的缺乏限制了SERS的应用,需要开发新的基底,研究其SERS活性,为获得高活性SERS基底引入新的血液。贵金属气凝胶是被广泛研究的功能多孔材料（FPMs）的一种,它不仅保留了气凝胶的种种特性,还继承了贵金属的特性（例如,高催化活性、高电导率和等离子特性）,而关于贵金属气凝胶的研究多集中于电化学性能测试,又由于其自身的特性也可用作SERS活性基底,但这方面的研究少之又少。因此本文采用新的方法调控气凝胶网络特征尺寸,系统研究气凝胶特征尺寸与SERS增强的关系,期望获得高活性SERS基底的设计原则,拓展了金气凝胶及其双金属气凝胶在内的贵金属气凝胶在SERS领域中的应用,这些结果对优化SERS活性底物的制备条件和阐明相关的SERS机制都有一定的意义。主要工作如下:（1）通过溶胶-凝胶法合成金气凝胶,利用不同的配体（如:聚乙烯吡咯烷酮、柠檬酸钠、脱氧胆矾酸钠等）及盐（如:NaCl、NH₄SCN等）诱导,从几纳米到几百纳米范围内控制金气凝胶的网络特征尺寸。如以聚乙烯吡咯烷酮为配体,加入HAuCl₄,用NaBH₄作为还原剂和引发剂,通过冷冻干燥法可以得到小尺寸的凝胶（<10nm）;以柠檬酸钠为配体,加入HAuCl₄,用NaBH₄作为还原剂,用KCl作引发剂,可以得到较大尺寸的凝胶（～80nm）。将其作为SERS活性基底,以罗丹明6G作为靶分子,研究基底尺寸与SERS增强信号的相关性。这些结果对于优化SERS活性底物的制备条件和阐明相关的SERS机理都可能是有意义的。（2）在前一个工作的基础上,用压力调节金气凝胶沿z-轴方向的距离,证明适当压缩的好处;并在此前提下,调整凝胶的组成（比如合成合金气凝胶）,再次调节z-轴距离,使得优化后的贵金属气凝胶显示出优异的SERS性能。希望以此能够进一步优化三维SERS基底,增强其拉曼信号的稳定性和均一性,推进其价值实际化的进展。更多还原

【Abstract】 As a powerful tool of detection,identification and analysis,Surface-enhanced Raman scattering（SERS）was considered to be one of the most practical surface analysis methods at the beginning of discovery.It has been used extensively in molecular structure discernment,biotic analysis and medical testing.Noble metals tied up a essential precinct in the field of SERS.Fact-finding have proclaim that highly porous and rough metal surfaces have obvious SERS effects.And the SERS activity is relative to the material and characteristic size of the substrate.However,the lack of the substrate limits the application of SERS.To obtain the highly active SERS substrates,It is necessary to develop a new substrate and study it’s SERS activity.Noble metal aerogels as a kind of functional porous materials（FPMs）that have been widely research.It not only retain the various features of the aerogel,but also inherit the characteristics of noble metals（for instance,high catalytic activity,high conductivity and plasma characteristics）.However,the researches on noble metal aerogels mostly focus on electrochemical performance testing,and their own characteristics can also be used as SERS active substrates,but there are few studies in this area.Therefore,this paper employ a new method to control the characteristic size of aerogels,systematically study the relationship between the characteristic size of aerogels and the enhancement of SERS,hope to obtain the design principle of high-activity SERS substrate.And expands the application scope of noble metal aerogels.These results have certain significance for optimizing the preparation conditions of SERS active substrates and elucidating the related SERS mechanism.The main work is as follows:（1）Synthesize gold aerogel by sol-gel method,and the characteristic network size of gold aerogel was controlled from few nanometers to hundreds of nanometers by different ligands and salt（such as polyvinylpyrrolidone,sodium citrate,sodium deoxychitrinate and NaCl,NH₄SCN）.For example,to obtained small size gel（<10nm）,using polyvinylpyrrolidone as ligand and adding HAuCl₄,and use NaBH₄as reducing agent and initiator by freeze-drying.The gold aerogel with larger size（～80nm）can be obtained by the formula that sodium citrate as ligand,HAuCl₄,NaBH₄and KCl is added.It was used as the SERS active substrate and Rhodamine6G was used as the target molecule to study the correlation between the size of the substrate and the enhanced signal of SERS.These results may be meaningful for optimizing the preparation conditions of SERS active substrates and elucidating the related SERS mechanism.（2）On the strength of the preceding learn,the height of the metal aerogels along the z-axis is adjusted by pressure to prove the benefit of properly compression.And under this premise,the composition of the gel（for example,synthetic alloy aerogel）was adjusted to makes the optimized precious metal aerogel show excellent SERS performance.It is sincerely hoped that this can further optimize the three-dimensional SERS substrates,enrich the stability and uniformity of Raman signal,and promote the progress of it’s value actualization.更多还原