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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2021/07/19
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Congratulations to Qi Sun for her new paper has been published in Nano Letters! Luminescence in molecular aggregates can be quenched either by intermolecular charge transfer or by forming a dipole-forbidden lower Frenkel exciton in H-aggregate. Taking intermolecular charge transfer and excitonic coupling into a threestate model through localized diabatization, we demonstrate that the low-lying intermolecular charge-transfer state could couple with the upper bright Frenkel exciton to form dipole-allowed S1 that lies below the dark state, which accounts for the recent experimentally discovered strong luminescence in organic light-emitting transistors (OLETs) system with DPA and dNaAnt herringbone aggregates. The condition of forming such bright state is that the electron and hole transfer integrals, te and th, are of the same sign, and should be notably larger than the excitonic coupling (J), that is , te × th > 2J2. This theoretical finding not only rationalizes recent experiments but unravels an exciting scenario where strong luminescence and high charge mobilities become compatible, which is a preferable condition for both OLETs and electrically pumped lasing. |
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2021/07/17
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Congratulations to Weitang Li for his new paper has been published in Nature Communications!
The nonlocal electron-phonon couplings in organic semiconductors responsible for the fluctuation of intermolecular transfer integrals has been the center of interest recently. Several irreconcilable scenarios coexist for the description of the nonlocal electron-phonon coupling, such as phonon-assisted transport, transient localization, and band-like transport. Through a nearly exact numerical study for the carrier mobility of the Holstein-Peierls model using the matrix product states approach, we locate the phonon-assisted transport, transient localization and band-like regimes as a function of the transfer integral (V) and the nonlocal electron-phonon couplings (ΔV), and their distinct transport behaviors are analyzed by carrier mobility, mean free path, optical conductivity and one-particle spectral function. We also identify an “intermediate regime” where none of the established pictures applies, and the generally perceived hopping regime is found to be at a very limited end in the proposed regime paradigm.
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2021/07/17
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Congratulations to Weitang Li for his new paper has been published in CJCU!
密度矩阵重正化群(DMRG)作为计算低维强关联体系强有力的方法为人熟知, 在量子化学电子结构计算中得到广泛应用. 最近几年, 含时密度矩阵重正化群(TD-DMRG)的理论取得较快发展, TD-DMRG逐渐成为复杂体系量子动力学理论模拟的重要新兴方法之一 . 本文综述了基于矩阵乘积态(MPS) 和矩阵乘积算符(MPO)的DMRG基本理论, 并重点介绍了若干最常见的TD-DMRG时间演化算法, 包括基于演化再压缩(P&C)的算法、基于含时变分原理(TDVP)的算法和时间步瞄准(TST)算法; 还对利用TD-DMRG模拟有限温体系的纯化(Purification)算法和最小纠缠典型量子热态(METTS)算法进行了介绍. 最后, 对近年TD-DMRG在复杂体系量子动力学中的应用进行了总结.
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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
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