Welcome to Zhigang Shuai Group !
Zhigang Shuai 帅志刚
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Office: S511, Meng Min Wei SciTech Building (蒙民伟科技大楼南楼511) Department of Chemistry Tel:+86-10-62797689 Researcher ID:H-5576-2011(H-index 79) |
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Honours and Awards
Journal Editorials
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Recent Selected papers
Please visit the web page Publications for the full list. |
Developing and applying new theoretical and computational methods
to study optoelectronic functional materials
The research in the Shuai Group involves theoretical and computational studies of phenomena in organic and polymeric functional materials.
A primary goal is to develop and apply new computational methods to explain and predict the opto-electronic functions of organic functional materials. For instance, we are interested in the charge/thermoelectric transports in organic semiconductors and carbon nano-ribbon and sheets, electronic excited state decay processes relevant to organic light-emitting quantum efficiency and spectrum, charge and exciton dynamics in polymer photovoltaics, thermoelectric figure of merits, nonlinear optical responses and multiphoton absorption, supramolecular self-assembly and disassembly.
These also include methods for correlated electron such as quantum chemistry density matrix renormalization group and equation of motion coupled cluster theory, both at semiempirical levels.
2021 News
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2021/06/17
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Congratulations to Ran Liu for his new paper has been published in CCS Chemistry!
The Seebeck effect measures the electric potential built up in materials under a temperature gradient. For organic thermoelectric materials, the Seebeck coefficient shows more complicated temperature dependence than conventional systems, with both monotonic increases and nonmonotonic behavior, that is, first increasing and then decreasing. The mechanism behind the phenomenon is intriguing. Through first-principles calculations coupled with the Boltzmann transport equation, we demonstrate typical trends of the Seebeck coefficient with respect to temperature through band structure analysis. The bandgap and bandwidths of the valence band and conduction band jointly determine the effectiveness of thermal activation. Ineffective or effective thermal activation leads to a one- or a two-band transport behavior, respectively. Under the thermal-activation mechanism, Seebeck coefficient shows monotonic temperature dependence in a one-band model but nonmonotonic relationship in a two-band model. In particular, in the two-band model, Seebeck coefficient might show an ambipolar behavior, that is, its sign changes at high temperature.
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2021/06/03
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Congratulations to Yuanheng Wang for his new paper has been published in J. Chem. Phys.!
In this work, we propose a new method to calculate molecular nonradiative electronic relaxation rates based on the numerically exact timedependent density matrix renormalization group theory. This method could go beyond the existing frameworks under the harmonic approximation (HA) of the potential energy surface (PES) so that the anharmonic effect could be considered, which is of vital importance when the electronic energy gap is much larger than the vibrational frequency. We calculate the internal conversion (IC) rates in a two-mode model with Morse potential to investigate the validity of HA. We find that HA is unsatisfactory unless only the lowest several vibrational states of the lower electronic state are involved in the transition process when the adiabatic excitation energy is relatively low. As the excitation energy increases, HA first underestimates and then overestimates the IC rates when the excited state PES shifts toward the dissociative side of the ground state PES. On the contrary, HA slightly overestimates the IC rates when the excited state PES shifts toward the repulsive side. In both cases, a higher temperature enlarges the error of HA. As a real example to demonstrate the effectiveness and scalability of the method, we calculate the IC rates of azulene from S1 to S0 on the ab initio anharmonic PES approximated by the one-mode representation. The calculated IC rates of azulene under HA are consistent with the analytically exact results. The rates on the anharmonic PES are 30%–40% higher than the rates under HA.
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2021/05/24
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Congratulations to Lu Wang !
Congratulations to Lu Wang for completing her PhD Dissertation Defense !
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2021/05/24
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Congratulations to Guodong Wang !
Congratulations to Guodong Wang for completing his PhD Dissertation Defense !
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2021/05/24
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Congratulations to Sheng Huang !
Congratulations to Sheng Huang for completing his Master Dissertation Defense !
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2021/03/28
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Congratulations to Yufei Ge on his published paper in Appl. Phys. Lett.! The Seebeck effect or thermopower relates the temperature gradient to the electric voltage drop. Seebeck coefficient a measures the transport entropy, which could either linearly increase with temperature T like metallic conducting or decrease as 1/T like semiconducting behavior. It could become more complicated in the temperature dependence for a number of disordered systems but still in a monotonic way. However, several recent experiments reported the “abnormal” non-monotonic temperature dependence of the Seebeck coefficient in doped conducting polymers, for instance, first increasing and then decreasing. Through a one-dimensional tight-binding model coupled with |
