本文關(guān)鍵詞： 準(zhǔn)分子激光 激光液相燒蝕法 貴金屬基核殼納米結(jié)構(gòu) 光致發(fā)光 光催化　出處：《北京工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：探索制備材料的新方法是納米材料學(xué)永恒的課題,核殼納米結(jié)構(gòu)以其單分散性好,可操作性高,穩(wěn)定性高以及具有自組裝性能而備受關(guān)注。納米結(jié)構(gòu)的性能優(yōu)劣取決于其制備方法,脈沖激光液相燒蝕法是一種簡(jiǎn)便,快速,適應(yīng)性廣,綠色的制備納米材料的方法。本文旨在研究采用248 nm準(zhǔn)分子脈沖激光液相燒蝕制備貴金屬基核殼納米結(jié)構(gòu)的制備工藝,以及制備產(chǎn)物的表征與產(chǎn)物性能的分析。本文采用248 nm準(zhǔn)分子激光在制備貴金屬單一納米結(jié)構(gòu),貴金屬核殼納米結(jié)構(gòu)和ZnO納米結(jié)構(gòu)的基礎(chǔ)上成功制備了Ag/ZnO核殼納米結(jié)構(gòu)。采用高分辨透射電子顯微鏡、紫外可見近紅外分光光度計(jì)、X射線衍射譜儀以及X射線光電子能譜儀對(duì)制備產(chǎn)物的形貌、成分、包覆情況與光吸收效果等進(jìn)行表征。結(jié)果表明:該方法制備的雙金屬核殼納米結(jié)構(gòu)與Ag/ZnO核殼納米結(jié)構(gòu)的表面等離共振特性可以通過控制殼層厚度進(jìn)行調(diào)節(jié),且這一現(xiàn)象與采用Mie理論模擬的核殼結(jié)構(gòu)的光吸收效果一致。采用共聚焦拉曼、光致發(fā)光譜和紫外輻照對(duì)制備產(chǎn)物的表面增強(qiáng)拉曼、光致發(fā)光以及光催化性能進(jìn)行表征。結(jié)果表明:激光燒蝕法制備的貴金屬核殼納米結(jié)構(gòu)具有很強(qiáng)的表面增強(qiáng)拉曼活性,可應(yīng)用于材料的痕量檢測(cè)領(lǐng)域;制備的Ag/ZnO核殼納米結(jié)構(gòu)的紫外發(fā)光比ZnO納米顆粒更強(qiáng)且產(chǎn)生藍(lán)移,經(jīng)分析表明紫外發(fā)光增強(qiáng)是由于Ag與ZnO之間存在電子轉(zhuǎn)移造成的,而峰位藍(lán)移是其納米結(jié)構(gòu)的量子尺寸效應(yīng)造成;Ag/ZnO核殼納米結(jié)構(gòu)具有良好的光催化效果且其光催化效果受Ag含量的影響。本文還結(jié)合實(shí)驗(yàn)對(duì)兩步法激光燒蝕制備核殼納米結(jié)構(gòu)的生成機(jī)制分為團(tuán)聚成核與殼層包覆兩個(gè)階段,并進(jìn)行了分析。
[Abstract]:Exploring new methods of preparing materials is an eternal subject in nanomaterials. Core-shell nanostructures have good monodispersity and high maneuverability. The properties of nanostructures depend on their preparation methods. Pulsed laser liquid phase ablation is a simple, rapid and adaptable method. The preparation process of noble metal based core shell nanostructures by liquid phase ablation with 248 nm excimer pulse laser was studied. In this paper, a 248nm excimer laser was used to prepare a single noble metal nanostructure. Ag/ZnO core-shell nanostructures were successfully prepared on the basis of noble metal core-shell nanostructures and ZnO nanostructures. The morphology and composition of the prepared products by UV-Vis near infrared spectrophotometer and X-ray diffraction spectrometer and X-ray photoelectron spectrometer. The results show that the surface isodissociation resonance of bimetallic core-shell nanostructures and Ag/ZnO core-shell nanostructures can be adjusted by controlling the shell thickness. This phenomenon is consistent with the optical absorption of the core-shell structure simulated by Mie theory. The surface enhanced Raman spectra of the prepared products are obtained by confocal Raman spectroscopy, photoluminescence and ultraviolet irradiation. The photoluminescence and photocatalytic properties were characterized. The results showed that the noble metal core-shell nanostructures prepared by laser ablation had strong surface-enhanced Raman activity and could be used in the field of trace detection of materials. The UV luminescence of the prepared Ag/ZnO core-shell nanostructures is stronger than that of ZnO nanoparticles and the blue shift is produced. The analysis shows that the enhancement of UV luminescence is due to the existence of electron transfer between Ag and ZnO. However, the blue shift of peak position is the quantum size effect of the nanostructure, which results in the good photocatalytic effect of Ag / ZnO core-shell nanostructure and the influence of Ag content on the photocatalytic effect. In this paper, the two-step laser ablation method is also used to prepare the nucleation. The formation mechanism of shell nanostructures can be divided into two stages: agglomeration nucleation and shell coating. And the analysis is carried out.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1

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本文編號(hào)：1505950