Electronic Transitions in Highly Symmetric Au<sub>130</sub> Nanoclusters
by Spectroelectrochemistry and Ultrafast Spectroscopy
Jonathan W. Padelford
Meng Zhou
Yuxiang Chen
Rongchao Jin
Gangli Wang
10.1021/acs.jpcc.7b07314.s001
https://acs.figshare.com/articles/journal_contribution/Electronic_Transitions_in_Highly_Symmetric_Au_sub_130_sub_Nanoclusters_by_Spectroelectrochemistry_and_Ultrafast_Spectroscopy/5427124
Rich and discrete energy states in
gold nanoclusters enable different combinations of electronic transitions
and correspondingly electrochemical and optical properties for a variety
of applications. The impacts on those electronic transitions by the
emergence and magnitude/alignment of a band gap and by the contributions
from different atomic/molecular orbitals require further study. Au
nanoclusters with 130 core Au atoms are of interest in this report
because they are at the transition size regime where a small yet well-defined
band gap can be resolved along with continuous quantized frontier
core orbitals. Here, electrochemical analysis is combined with UV–vis–near
infrared optical measurements to unveil previously unresolved electronic
transitions. Finite changes in the steady-state optical absorption
spectrum are captured by spectroelectrochemistry when the Au nanoclusters
are charged to different states via electrolysis. Multiple previously
unresolved peaks and valleys as well as isosbestic “points/regions”
are observed in the differential spectrum. The detailed spectral features
are explained by the respective electronic transitions to those affected
energy states. Key features are also well correlated with ultrafast
absorption analysis which provides additional insights, such as the
lifetime of the corresponding transitions. The experimentally measured
energy states and transitions could serve as references for future
theoretical study to learn the respective contributions from different
atomic orbitals and, importantly, to explore routes to enhance or
suppress certain transition so as to modulate the corresponding electrochemical
and optical properties for better applications.
2017-09-08 00:00:00
Ultrafast Spectroscopy Rich
nanocluster
electrochemical
band gap
UV
transition size regime
energy states
ultrafast absorption analysis
quantized frontier core orbitals