銅原子摻雜對(duì)金表面三聚氰胺自組裝結(jié)構(gòu)的調(diào)控
發(fā)布時(shí)間：2018-09-08 20:37
【摘要】：分子自組裝膜由于其自發(fā)性、高度有序性、以及可設(shè)計(jì)性等特點(diǎn),長(zhǎng)期以來(lái)被認(rèn)為是一種自下而上構(gòu)筑納米結(jié)構(gòu)的有效方法。大量的分子自組裝研究均以金屬單質(zhì)表面作為襯底,這與實(shí)際應(yīng)用中廣泛存在的多組分金屬表面即合金化表面相差甚遠(yuǎn)。實(shí)際上,表面合金結(jié)構(gòu)往往展現(xiàn)出有別于單組分金屬表面的各種性質(zhì),在催化等領(lǐng)域應(yīng)用廣泛。然而目前人們對(duì)合金體系的表面科學(xué)基礎(chǔ)研究仍然比較有限,所涉及的分子吸附及反應(yīng)也多限于CO、O2等小分子,而對(duì)具有廣泛應(yīng)用前景的各種功能性有機(jī)分子在合金表面的吸附組裝及反應(yīng)研究則幾乎是空白。故此,我們選擇了有重要應(yīng)用背景的Au-Cu合金體系,并在前期詳細(xì)研究Cu/Au(111)薄膜結(jié)構(gòu)與性質(zhì)的基礎(chǔ)上,進(jìn)一步制備了只有一到幾個(gè)原子層厚度的Au/Cu(111)薄膜。我們進(jìn)而利用掃描隧道顯微鏡(STM)結(jié)合同步輻射及x射線光電子能譜技術(shù)(PES)詳細(xì)研究了這些金薄膜的原子結(jié)構(gòu)與電子性質(zhì)以及三聚氰胺分子在其表面的吸附組裝行為。研究發(fā)現(xiàn):(1)3層及以下的Au薄膜的原子晶格小于Au(111)表面晶格而大于Cu(111)表面晶格,且隨著層數(shù)增加而增大;4層及以上的Au薄膜才回歸到Au(111)晶格。各層Au薄膜的電子性質(zhì)也基本上按照原子晶格的變化規(guī)律而逐漸回歸至Au(111)表面性質(zhì)。(2)PES研究表明,襯底Cu原子滲析到Au薄膜表面,并隨著Au膜厚度的增加而減少。直至7層金膜表面仍能觀察到一定量的Cu。(3)三聚氰胺分子優(yōu)先吸附在裸露的襯底Cu(111)表面并形成與純凈Cu(111)表面一致的組裝結(jié)構(gòu),至飽和后才開(kāi)始在金薄膜表面吸附。(4)三聚氰胺在Au膜上的組裝結(jié)果受到滲析至金薄膜表面的Cu原子的影響而形成新穎的組裝結(jié)構(gòu),其結(jié)構(gòu)花樣隨著Au薄膜厚度即表面Cu原子的數(shù)量而變化,最終回歸Au(111)表面的組裝結(jié)果。作為對(duì)照,我們還在預(yù)吸附有三聚氰胺自組裝薄膜的Au(111)表面蒸鍍Cu原子。通過(guò)控制Cu原子的蒸鍍量,實(shí)現(xiàn)了將三聚氰胺組裝結(jié)構(gòu)逐步調(diào)變至在Au/CU(111)表面形成的多種組裝結(jié)構(gòu)。經(jīng)過(guò)兩個(gè)體系的對(duì)比研究,進(jìn)一步佐證了Cu原子的摻雜對(duì)三聚氰胺分子在金薄膜表面組裝結(jié)構(gòu)的調(diào)控作用。在本論文的最后一部分,我們嘗試研究了另外一種有望制備二維共價(jià)網(wǎng)格結(jié)構(gòu)的1,3,5-苯三腈分子,表征并分析了其在Cu(111)和Au(111)表面的自組裝結(jié)構(gòu),為進(jìn)一步研究其在Cu/Au(111)、Au/Cu(111)薄膜表面的吸附組裝以及制備高度有序的二維共價(jià)有機(jī)框架結(jié)構(gòu)打下了基礎(chǔ)。
[Abstract]:Molecular self-assembled films have long been considered as an effective way to construct nanostructures from the bottom up due to their characteristics of spontaneity, high order and designability. A large number of molecular self-assembly studies have been carried out on a single metal substrate, which is far from the multicomponent metal surface, i.e. alloying surface, which is widely used in practical applications. As a matter of fact, the structure of surface alloys often shows a variety of properties different from that of single component metals, and is widely used in catalysis and other fields. However, at present, the basic research on surface science of alloy system is still limited, and the molecular adsorption and reaction involved are limited to small molecules such as CO,O2. However, the adsorption, assembly and reaction of various functional organic molecules with wide application prospects on the alloy surface are almost blank. Therefore, we have selected the Au-Cu alloy system with important application background, and on the basis of detailed investigation of the structure and properties of Cu/Au (111) thin films, we have further prepared Au/Cu (111) thin films with only one or several atomic layers. Furthermore, the atomic structure and electronic properties of these gold thin films and the adsorption and assembly behavior of melamine molecules on their surface have been studied in detail by scanning tunneling microscope (STM) combined with synchrotron radiation and X-ray photoelectron spectroscopy (PES). It is found that (1) the atomic lattice of Au thin films with layers 3 and below is smaller than that of Au (111) and is larger than that of Cu (111), and the Au films with 4 or more layers increase with the increase of the number of layers before returning to Au (111) lattices. The electronic properties of each layer of Au thin films are also gradually regressed to the surface properties of Au (111) according to the variation of atomic lattice. (2) PES study shows that the Cu atoms on the substrate are dialyzed to the surface of Au films and decrease with the increase of the thickness of Au films. Cu. (3) melamine molecules were preferentially adsorbed on the Cu (111) surface of the bare substrate and formed an assembly structure consistent with that of the pure Cu (111) surface. (4) the results of melamine assembly on Au films were influenced by the Cu atoms on the surface of gold films, and formed a novel assembly structure. The structure pattern changes with the thickness of the Au film, that is, the number of Cu atoms on the surface, and finally returns to the assembly result of the Au (111) surface. As a control, we also vaporized Cu atoms on the surface of Au (111) on which melamine self-assembled films were preadsorbed. By controlling the amount of vaporization of Cu atoms, the melamine assembly structure was gradually adjusted to a variety of assembly structures formed on the surface of Au/CU (111). Through the comparative study of the two systems, the effect of doping of Cu atoms on the structure of melamine molecules on the surface of gold films was further verified. In the last part of this thesis, we try to study another kind of molecule which is expected to prepare two-dimensional covalent lattice structure, and characterize and analyze its self-assembly structure on the surface of Cu (111) and Au (111). The results provide a basis for the further study of the adsorption and assembly on the surface of Cu/Au (111) au / Cu (111) films and the preparation of highly ordered two-dimensional covalent organic frameworks.
【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.2;O641.3
本文編號(hào)：2231630
[Abstract]:Molecular self-assembled films have long been considered as an effective way to construct nanostructures from the bottom up due to their characteristics of spontaneity, high order and designability. A large number of molecular self-assembly studies have been carried out on a single metal substrate, which is far from the multicomponent metal surface, i.e. alloying surface, which is widely used in practical applications. As a matter of fact, the structure of surface alloys often shows a variety of properties different from that of single component metals, and is widely used in catalysis and other fields. However, at present, the basic research on surface science of alloy system is still limited, and the molecular adsorption and reaction involved are limited to small molecules such as CO,O2. However, the adsorption, assembly and reaction of various functional organic molecules with wide application prospects on the alloy surface are almost blank. Therefore, we have selected the Au-Cu alloy system with important application background, and on the basis of detailed investigation of the structure and properties of Cu/Au (111) thin films, we have further prepared Au/Cu (111) thin films with only one or several atomic layers. Furthermore, the atomic structure and electronic properties of these gold thin films and the adsorption and assembly behavior of melamine molecules on their surface have been studied in detail by scanning tunneling microscope (STM) combined with synchrotron radiation and X-ray photoelectron spectroscopy (PES). It is found that (1) the atomic lattice of Au thin films with layers 3 and below is smaller than that of Au (111) and is larger than that of Cu (111), and the Au films with 4 or more layers increase with the increase of the number of layers before returning to Au (111) lattices. The electronic properties of each layer of Au thin films are also gradually regressed to the surface properties of Au (111) according to the variation of atomic lattice. (2) PES study shows that the Cu atoms on the substrate are dialyzed to the surface of Au films and decrease with the increase of the thickness of Au films. Cu. (3) melamine molecules were preferentially adsorbed on the Cu (111) surface of the bare substrate and formed an assembly structure consistent with that of the pure Cu (111) surface. (4) the results of melamine assembly on Au films were influenced by the Cu atoms on the surface of gold films, and formed a novel assembly structure. The structure pattern changes with the thickness of the Au film, that is, the number of Cu atoms on the surface, and finally returns to the assembly result of the Au (111) surface. As a control, we also vaporized Cu atoms on the surface of Au (111) on which melamine self-assembled films were preadsorbed. By controlling the amount of vaporization of Cu atoms, the melamine assembly structure was gradually adjusted to a variety of assembly structures formed on the surface of Au/CU (111). Through the comparative study of the two systems, the effect of doping of Cu atoms on the structure of melamine molecules on the surface of gold films was further verified. In the last part of this thesis, we try to study another kind of molecule which is expected to prepare two-dimensional covalent lattice structure, and characterize and analyze its self-assembly structure on the surface of Cu (111) and Au (111). The results provide a basis for the further study of the adsorption and assembly on the surface of Cu/Au (111) au / Cu (111) films and the preparation of highly ordered two-dimensional covalent organic frameworks.
【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.2;O641.3
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 張建祥,趙彥巧,陳吉祥,王日杰,張繼炎;CO_2加氫合成甲醇及二甲醚研究進(jìn)展[J];天然氣化工;2004年06期
2 高俊文,張勇,霍尚義;國(guó)內(nèi)外合成甲醇催化劑研究進(jìn)展[J];工業(yè)催化;1999年05期
，本文編號(hào)：2231630
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