Juarez-Mosqueda Rosalba, Malola Sami, Häkkinen Hannu
Department of Physics, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland.
Phys Chem Chem Phys. 2017 May 31;19(21):13868-13874. doi: 10.1039/c7cp01440f.
In this work, we used density functional theory (DFT) and linear response time-dependent DFT (LR-TDDFT) to investigate the stability, electronic structure, and optical properties of Au-doped [AgAu(BDT)(TPP)] nanoclusters (BDT: 1,3-benzenedithiol; TPP triphenylphosphine) with x = 0-5. The aim of this work is to shed light on the most favorable doped structures by comparing our results with previously published experimental data. The calculated relative energies, ranging between 0.8 and 10 meV per atom, indicate that several doped AgAu nanoclusters are likely to co-exist at room temperature. However, only the Au-doped [AgAu(BDT)(TPP)] nanoclusters that have direct bonding between Au dopants and phosphines display an enhancement in the electronic transitions at ∼450 nm. This agrees with the main spectral absorption features that have been experimentally reported for the mixture of Au-doped silver AgAu nanoclusters. In addition, the formation of the Au-TPP bond could prevent cluster degradation starting from the detachment of the phosphine molecules, since the Au-TPP bond is stronger by ∼0.4 eV than the analogous Ag-TPP one. Thus, the results presented here show the important role of Au-TPP bonding in determining the stability and optical properties of thiolate/phosphine-protected AgAu nanoclusters.
在这项工作中，我们使用密度泛函理论（DFT）和含时线性响应密度泛函理论（LR - TDDFT）来研究x = 0 - 5的金掺杂[AgAu(BDT)(TPP)]纳米团簇（BDT：1,3 - 苯二硫醇；TPP：三苯基膦）的稳定性、电子结构和光学性质。这项工作的目的是通过将我们的结果与先前发表的实验数据进行比较，来揭示最有利的掺杂结构。计算得到的相对能量范围为每个原子0.8至10毫电子伏特，这表明几种掺杂的AgAu纳米团簇在室温下可能共存。然而，只有金掺杂剂与膦之间存在直接键合的[AgAu(BDT)(TPP)]纳米团簇在约450纳米处的电子跃迁有增强。这与已报道的金掺杂银AgAu纳米团簇混合物的主要光谱吸收特征相符。此外，Au - TPP键的形成可以防止从膦分子脱离开始的团簇降解，因为Au - TPP键比类似的Ag - TPP键强约0.4电子伏特。因此，这里给出的结果表明Au - TPP键合在决定硫醇盐/膦保护的AgAu纳米团簇的稳定性和光学性质方面起着重要作用。
