Chen Shuang, Higaki Tatsuya, Ma Hedi, Zhu Manzhou, Jin Rongchao, Wang Gangli
Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, People's Republic of China.
Key Laboratory of Structure and Functional Regulation of Hybrid Materials, Ministry of Education, Anhui University, Hefei, 230601, People's Republic of China.
ACS Nano. 2020 Dec 22;14(12):16781-16790. doi: 10.1021/acsnano.0c04914. Epub 2020 Nov 16.
Small differences in electronic structures, such as an emerging energy band gaps or the splitting of degenerated orbitals, are very challenging to resolve but important for nanomaterials properties. A signature electrochemical property called quantized double layer charging, , "continuous" one-electron transfers (1e, ETs), in atomically precise Au(TBBT), Au(BM), and Au(TBBT) is analyzed to reveal the nonmetallic to metallic transitions (whereas TBBT is 4--butylbenzenethiol and BM is benzyl mercaptan; abbreviated as Au, Au, and Au). Subhundred milli-eV energy differences are resolved among the "often-approximated uniform" peak spacings from multipairs of reversible redox peaks in voltammetric analysis, with single ETs as internal standards for calibration and under temperature variations. Cyclic and differential pulse voltammetry experiments reveal a 0.15 eV energy gap for Au and a 0.17 eV gap for Au at 298 K. Au is confirmed metallic, displaying a "bulk-continuum" charging response without an energy gap. The energy gaps and double layer capacitances of Au and Au increase as the temperature decreases. The temperature dependences of charging energies and HOMO-LUMO gaps of Au and Au are attributed to the counterion permeation and the steric hindrance of ligand, as well as their molecular compositions. With the subtle energy differences resolved, spectroelectrochemistry features of Au and Au are compared with ultrafast spectroscopy to demonstrate a generalizable analysis approach to correlate steady-state and transient energy diagram for the energy-in processes. Electrochemiluminescence (ECL), one of the energy-out processes after the charge transfer reactions, is reported for the three samples. The ECL intensity of Au is negligible, whereas the ECLs of Au and Au are relatively stronger and observable (but orders of magnitudes weaker than our recently reported bimetallic AuAg). Results from these atomically precise nanoclusters also demonstrate that the combined voltammetric and spectroscopic analyses, together with temperature variations, are powerful tools to reveal subtle differences and gain insights otherwise inaccessible in other nanomaterials.
电子结构中的微小差异，例如新兴的能带隙或简并轨道的分裂，很难分辨，但对纳米材料的性质很重要。对原子精确的Au(TBBT)、Au(BM)和Au中一种称为量子化双层充电的标志性电化学性质，即“连续”单电子转移(1e, ETs)进行了分析，以揭示从非金属到金属的转变(其中TBBT是4-丁基苯硫醇，BM是苄基硫醇；简称为Au、Au和Au)。在伏安分析中，以单电子转移作为校准的内标，并在温度变化的情况下，分辨出多对可逆氧化还原峰的“常被近似为均匀”的峰间距之间小于百毫电子伏特的能量差异。循环伏安法和差分脉冲伏安法实验表明，在298 K时，Au的能隙为0.15 eV，Au的能隙为0.17 eV。Au被确认为金属，显示出“体连续”充电响应，没有能隙。Au和Au的能隙和双层电容随着温度的降低而增加。Au和Au的充电能量和HOMO-LUMO能隙的温度依赖性归因于抗衡离子渗透、配体的空间位阻及其分子组成。随着微小能量差异的分辨，将Au和Au的光谱电化学特征与超快光谱进行比较，以证明一种可推广的分析方法，用于关联能量输入过程的稳态和瞬态能量图。报道了这三个样品的电化学发光(ECL)，这是电荷转移反应后的能量输出过程之一。Au的ECL强度可以忽略不计，而Au和Au的ECL相对较强且可观察到(但比我们最近报道的双金属AuAg弱几个数量级)。这些原子精确的纳米团簇的结果还表明，伏安法和光谱分析相结合，再加上温度变化，是揭示其他纳米材料中难以察觉的细微差异并深入了解其性质的有力工具。
Analyst. 2014-4-21
Acc Chem Res. 2017-1-12
Nanoscale. 2021-11-11
J Am Chem Soc. 2018-4-19
Acc Chem Res. 2019-1-15
Top Curr Chem (Cham). 2025-9-8
ACS Cent Sci. 2025-7-14
Chem Sci. 2022-6-17
Zotero 插件