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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2021/03/28
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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 the Boltzmann transport equation, we investigate theoretically the doping effect for the Seebeck coefficient. We find that the abnormal behavior comes from multi bands’ contribution and a two-band model (conduction or valence band plus a narrow polaronic band) can address such an abnormal Seebeck effect, namely, if there exists (i) a small bandgap accessible for thermal activation between the two bands; and (ii) a large difference in the bandwidth between the polaronic band and the conduction band (or valence band), then the Seebeck coefficient increases with temperature first, then levels off, and finally drops down. |
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2021/03/18
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Congratulations to Shiyun Lin on her published paper in J. Phys. Chem. Lett. ! The two-coordinate carbene−metal−amide complexes have attracted a great deal of attention due to their remarkable thermally activated delayed fluorescence (TADF) properties, giving them promise in organic light-emitting diode application. To reveal the inherent mechanism, we take CAAC−Cu(I)−Cz and CAAC−Au(I)−Cz as examples to investigate the photophysical properties in solution and solid phases by combining quantum mechanics/molecular mechanics approaches for the electronic structure and the thermal vibration correlation function formalism for the excited-state decay rates. We found that both intersystem crossing (ISC) and its reverse (rISC) are enhanced by 2−4 orders of magnitude upon aggregation, leading to highly efficient TADF, because (i) the metal proportion in the frontier molecular orbitals increases, leading to an enhanced spin−orbit coupling strength between S1 and T1, and (ii) the reaction barriers for ISC and rISC are much lower in solution than in aggregate phases through a decrease in energy gap ΔEST and an increase in the relative reorganization energy through bending the angle ∠C2−Cu−N1 for T1. We propose a pump−probe time-resolved infrared spectroscopy study to verify the mechanism. These findings can clarify the ongoing dispute over the understanding of the high TADF quantum efficiency for two-coordinate metal complexes. |
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2021/03/15
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Congratulations to Sheng Huang on his published paper in J. Mater. Chem. A ! Integration of ferroelectricity into van der Waals heterostructures offers additional opportunities to control over the properties and functionalities of heterostructures by switching the direction of polarization via an external electric field. To discover potential ferroelectric monolayers that exhibit out-of-plane electric polarizations, we screen a family of metal phosphorus trichalcogenides M1M2P2X6 with M1= Cu/Ag, M2 = In/Bi, X = S/Se using density functional theory calculations. We predict room-temperature ferroelectricity/ in CuInP2S6 and CuBiP2S6 monolayers with out-of-plane polarizations (Ps) of 0.59 μC cm-2 and 0.35 μC cm-2, respectively. The strong metal-chalcogenide M1-X bond in the two Cu and S-based systems is responsible for their high phase transition temperatures. The polarizations in ferroelectric monolayers can persist in van der Waals heterostructures, and band gaps as well as band alignment of the heterostructures can be tuned by switching the polarization direction. Finally, we demonstrate that both visible light absorption and type-II band alignment facilitating fast charge separation can be realized in CuInP2S6/Mn2P2S6 and CuInP2S6/Zn2P2Se6 ferroelectric heterostructures, which are promising for applications in photocatalytic water |
