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| 題名: | 溴苯、溴噻吩及其衍生物在金(111)之吸附;Adsorption of Bromobenzene, Bromothiophene, and Their Derivatives on Au(111) |
| 作者: | 謝喬安;Hsieh, Chiao-An |
| 貢獻者: | 化學學系 |
| 關鍵詞: | 掃描式穿隧顯微鏡;循環伏安法;金(111);溴苯;溴噻吩;電化學;STM;CV;Au(111);Bromobenzene;Bromothiophene;electrochemistry |
| 日期: | 2025-07-17 |
| 上傳時間: | 2025-10-17 11:17:12 (UTC+8) |
| 出版者: | 國立中央大學 |
| 摘要: | 本研究結合循環伏安法(Cyclic Voltammetry, CV)與原位掃描式穿隧顯微鏡(Scanning Tunneling Microscope, STM)，系統性探討三類含溴有機分子於金(111)電極表面的吸附行為與電化學反應。
首先，溴苯(Bromobenzene, BrB)吸附會立即破壞金(111)表面的重排結構，導致由(√3×22)相轉變為(1×1)相，並生成約 2.3 Å 深的原子坑洞。BrB 與金吸附原子(Au adatoms)作用為主要機制。隨電位提升，BrB 的排列由一維鏈狀轉為二維有序陣列，最終形成三維多層薄膜，吸附方向也由平躺轉為直立。負電位下薄膜可脫附，並且BrB會在更負的電位下還原分解。與硫酸相比，過氯酸環境下 BrB 展現出不同的排列與局部結構，顯示陰離子的角色對吸附組裝具關鍵影響。
其次，2-溴噻吩(2-Bromothiophene, BrT)因具雙官能基(溴與硫)，展現雙末端吸附特性。CV 觀察到 BrT 可抑制亞硫酸氫根(bisulfate)的吸附，STM 顯示其可導致金(111)重排結構消失，並依電位調變形成 (3×3)、(3×2√3)的有序排列；當電位高於 0.9 V 時，BrT 發生不可逆氧化聚合，生成寡聚噻吩鏈(Oligothiophene)。在負電位下，BrT也會發生不可逆的還原分解。過氯酸環境下 BrT依電位展現出不同的排列結構(4×√31)、(√7×√13) 。
最後，對稱型有機分子 DTPPr-2Br、DTPPr-4Br 與 PPr-4Br，因極性趨近於0 D，主要透過π電子(π-electrons)與凡得瓦力吸附於金表面，其不會改變金(111)重排結構，正電位下形成穩定有序的多層薄膜，有利於鈣鈦礦太陽能電池中電荷傳輸。隨電位越正，其吸附結構會從有序轉換至無序；在負電位下發生脫附但並不會分解。;This study combines cyclic voltammetry (CV) and in situ scanning tunneling microscopy (STM) to systematically investigate the adsorption behavior and electrochemical reactivity of three types of organobromine molecules on Au(111) electrode surfaces.
First, bromobenzene (BrB) adsorption instantly disrupts the reconstructed structure of Au(111), transforming it from the (√3×22) herringbone phase to the (1×1) structure and generating ~2.3 Å deep atomic pits. This transformation is primarily driven by interactions between BrB and Au adatoms. With increasing potential, BrB molecules transition from forming 1D chains to 2D ordered arrays, and eventually assemble into vertically aligned 3D multilayer films. Under negative potentials, the BrB film can desorb, and at more negative potentials, it undergoes irreversible reductive decomposition. Compared to sulfuric acid, BrB exhibits distinct local arrangements and packing behavior in perchloric acid, highlighting the critical role of electrolyte anions in interfacial molecular assembly.
Second, 2-bromothiophene (BrT) features dual anchoring capability of BrT via its bromine and sulfur functional groups, CV results show that BrT suppresses bisulfate (HSO₄⁻) adsorption, while STM imaging reveals that it eliminates the Au(111) surface reconstruction and forms ordered structures such as (3×3) and (3×2√3) depending on the applied potential. At potentials above 0.9 V, BrT undergoes irreversible oxidative polymerization to form oligothiophene chains. At negative potentials, BrT also undergoes irreversible reductive decomposition. In perchloric acid, BrT assembles into dirrerent ordered phases, such as (4×√31) and (√7×√13), further emphasizing anion-dependent structural control.
Lastly, symmetric organic molecules DTPPr-2Br, DTPPr-4Br, and PPr-4Br—with dipole moments approaching 0 D—adsorb onto Au(111) primarily through π-electron interactions and van der Waals forces. These molecules do not perturb the reconstructed gold surface. Under positive potentials, they form stable, ordered multilayer films conducive to charge transport in perovskite solar cells. As the potential increases further, the adsorbed layers become disordered. Under negative potentials, the molecules desorb without undergoing decomposition. |
| 顯示於類別: | [化學研究所] 博碩士論文
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