Electronic relaxation dynamics in [Au 25 (SR) 18 ] −1 (R = CH 3 , C 2 H 5 , C 3 H 7 , MPA, PET) thiolate-protected nanoclusters
Electronic relaxation dynamics in [Au 25 (SR) 18 ] −1 (R = CH 3 , C 2 H 5 , C 3 H 7 , MPA, PET) thiolate-protected nanoclusters
复制标题
[Au 25 (SR) 18 ] â1 (R = CH 3 , C 2 H 5 , C 3 H 7 , MPA, PET) 硫醇盐保护的纳米团簇中的电子弛豫动力学
DOI：
10.1039/c9cp04039k
复制
发表时间：
2020
影响因子：
3.3
通讯作者：
Aikens, Christine M.
中科院分区：
文献类型：
--
作者：
Senanayake, Ravithree D.;Aikens, Christine M.
我们研究了[Au 25（SR）18]−1（R = CH 3，C2 H5，C3 H7，MPA，PET）[MPA =巯基丙酸，PET =苯乙硫醇]纳米粒子中的激发态电子动力学，以了解不同配体如何影响该系统中的激发态动力学。使用实时密度泛函方法中的表面跳跃方法和退相干校正，研究了能量范围为0.00-2.20 eV的核心和更高激发态的布居动力学。所有连接的簇遵循核心状态（S1-S6）的类似衰减趋势。观测到的时间常数在皮秒时间尺度（2-19 ps）上，与实验时间尺度一致，证实了实验观测到的时间常数可能来源于核-核跃迁，而不是核-半环跃迁.在较高激发态的存在下，R = H、CH 3、C2 H5、C3 H7和PET表现出类似的弛豫趋势，而R = MPA由于其电子结构中LUMO+1和LUMO+2间隙之间的间隙较小而显示出略微不同的核心状态弛豫。S1（HOMO → LUMO）态在所有连接的团簇中衰变最慢，而S7有相对较长的衰变。此外，在[Au 25（SCH 3）18]−1纳米团簇上进行了单独的电子和空穴弛豫，以了解独立的电子和空穴弛豫如何对整体弛豫动力学做出贡献。
We investigate the excited electron dynamics in [Au25(SR)18]−1 (R = CH3, C2H5, C3H7, MPA, PET) [MPA = mercaptopropanoic acid, PET = phenylethylthiol] nanoparticles to understand how different ligands affect the excited state dynamics in this system. The population dynamics of the core and higher excited states lying in the energy range 0.00–2.20 eV are studied using a surface hopping method with decoherence correction in a real-time DFT approach. All of the ligated clusters follow a similar trend in decay for the core states (S1–S6). The observed time constants are on the picosecond time scale (2–19 ps), which agrees with the experimental time scale, and this study confirms that the time constants observed experimentally could originate from core-to-core transitions and not from core-to-semiring transitions. In the presence of higher excited states, R = H, CH3, C2H5, C3H7, and PET demonstrate similar relaxations trends whereas R = MPA shows slightly different relaxation of the core states due to a smaller gap between the LUMO+1 and LUMO+2 gap in its electronic structure. The S1 (HOMO → LUMO) state gives the slowest decay in all ligated clusters, while S7 has a relatively long decay. Furthermore, separate electron and hole relaxations were performed on the [Au25(SCH3)18]−1 nanocluster to understand how independent electron and hole relaxations contribute to the overall relaxation dynamics.