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Georgia Ivanova Nadezhda Bozova Nikolay Petkov Dr. Cunbin An Dr. Benlin Hu Monika Mutovska Konstantin Konstantinov Dr. Yulian Zagranyarski Dr. Vladimira Videva Adelina Yordanova Prof. Martin Baumgarten Prof. Anela Ivanova 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(16):e202104411
Computational modeling of the optical characteristics of organic molecules with potential for thermally activated delayed fluorescence (TADF) may assist markedly the development of more efficient emitting materials for organic light-emitting diodes. Recent theoretical studies in this area employ mostly methods from density functional theory (DFT). In order to obtain accurate predictions within this approach, the choice of a proper functional is crucial. In the current study, we focus on testing the performance of a set of DFT functionals for estimation of the excitation and emission energy and the excited singlet-triplet energy gap of three newly synthesized compounds with capacity for TADF. The emitters are designed specifically to enable charge transfer by π-electron conjugation, at the same time possessing high-energy excited triplet states. The functionals chosen for testing are from various groups ranging from gradient-corrected through global hybrids to range-separated ones. The results show that the monitored optical properties are especially sensitive to how the long-range part of the exchange energy is treated within the functional. The accurate functional should also be able to provide well balanced distribution of the π-electrons among the molecular fragments. Global hybrids with moderate (less than 0.4) share of exact exchange (B3LYP, PBE0) and the meta-GGA HSE06 are outlined as the best performing methods for the systems under study. They can predict all important optical parameters correctly, both qualitatively and quantitatively. 相似文献
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Zhou Shuiping Zhou Xiaoyang Tang Gen Guo Xiang Pang Aimin 《Journal of Thermal Analysis and Calorimetry》2020,140(5):2529-2540
Journal of Thermal Analysis and Calorimetry - Differences of thermal decomposition characteristics and combustion properties between CL-20-based propellants and HMX-based propellants were... 相似文献
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Dr. Shaomin Peng Dr. Qi Wei Dr. Bingzhe Wang Dr. Zhipeng Zhang Hongcheng Yang Guotao Pang Prof. Kai Wang Prof. Guichuan Xing Prof. Xiao Wei Sun Prof. Zikang Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22340-22346
Quasi-two-dimensional (2D) perovskites are promising candidates for light generation owing to their high radiative rates. However, strong exciton–phonon interactions caused by mechanical softening of the surface act as a bottleneck in improving their suitability for a wide range of lighting and display applications. Moreover, it is not easily available to tune the phonon interactions in bulk films. Here, we adopt bottom-up fabricated blue emissive perovskite nanoplatelets (NPLs) as model systems to elucidate and as well as tune the phonon interactions via engineering of binary NPL solids. By optimizing component domains, the phonon coupling strength can be reduced by a factor of 2 driven by the delocalization of 2D excitons in out-of-plane orientations. It shows the picosecond energy transfer originated from the Förster resonance energy transfer (FRET) efficiently competes with the exciton–phonon interactions in the binary system. 相似文献
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The Ni? Mo/Mg(OH)2 (NMM) hybrid as an efficient flame retardancy and smoke suppression composite for polypropylene (PP) was synthesized through Ni? Mo co‐precipitation on the surface of Mg(OH)2 (MH) hexagonal nanosheets. Compared to PP/MH, PP/NMM exhibited excellent smoke suppressing and flame retardancy on the heat release rate, total heat release, smoke production rate, total smoke production, CO production rate and total CO production with the same loading. The reduced hazard of PP/NMM was mainly attributed to the high physical barrier effect of compact char residues on heat, smoke and combustible gas. The mechanism study indicated that multiwalled carbon nanotubes (MWCNTs) generated from the catalytic carbonization of PP by the Ni? Mo compound could play the role of “rebar” to strengthen the char residues, avoid the generation of cracks and form highly compact char layer. Furthermore, MgO could facilitate the production of MWCNTs through changing the pyrolysis process of PP and increasing the reaction time between pyrolysis gas and Ni? Mo compound. Hence, the new Ni? Mo/MH catalyst hybrid may explore the potential for solving the tough problem of the flammability and heavy smoke of the polyolefins system. 相似文献
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An incremental bundle method for portfolio selection problem under second-order stochastic dominance
Numerical Algorithms - We propose a preconditioner to accelerate the convergence of the GMRES iterative method for solving the system of linear equations obtained from discretize-then-optimize... 相似文献
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Russian Journal of Physical Chemistry A - Preparation of highly homogeneous disperse ions multi-walled carbon nanotubes (MWCNTs) has vital effect on their applications. In this research, the... 相似文献
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