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Chin-Kuen Tai Pao-Ling Yeh Chun-Chi Chang Wen-Hao Chen Rong-Hou Wu Yu-Ma Chou Bo-Cheng Wang 《Research on Chemical Intermediates》2014,40(6):2355-2362
Recently, the organic synthesis and electronic device applications of π-conjugated polymer-based materials with low energy band gap (below 2 eV) and high values of incident photon to current efficiency have been presented. In the present study, the physical properties of polythiophene (PTH) and its derivative systems (PTs) were investigated as π-conjugated low energy band gap polymers. Density functional theory with periodic boundary condition (PBC), the B3LYP functional, and the 6-31G(d) basis set was applied to determine their geometric and electronic structures and corresponding energies (E HOMO, E LUMO, and E g = E LUMO ? E HOMO) from the monomer of thiophene and its derivatives for one-dimensional (1D) extension to polymer. The effects of 3-substitution in PTs including electron-donating (CH3–, C6H13–, OH–, Cl–, OCH3–, and CHO–) and electron-withdrawing groups (Cl–, CHO–, CN–, NO2–, CF3–, and COOH–) compared with PTH were investigated. According to the calculation results, PTs with electron-donating and electron-withdrawing substituents should exhibit red- and blue-shifts, respectively, compared with PTH. These calculation results show good agreement with experimental data and provide further information for molecular design considerations. 相似文献
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Effects of substituent and solvent on the structure and spectral properties of maleimide derivatives
Chin-Kuen Tai Yih-Jiun Lin Pao-Ling Yeh Yi-Ren Tzeng Yu-Ma Chou Bo-Cheng Wang 《Journal of Molecular Structure》2008,860(1-3):58-63
The maximum absorption wavelength , emission wavelength (λem) and the related oscillator strength (f) of the maleimides in the ground and first excited states were calculated by using the DFT, CIS and the time-dependent density functional theory (TD-DFT) methods, where the molecular structures were optimized by DFT/B3LYP/6-31G* calculation. Solvent effects on the maleimides were examined using the PCM simulation at DFT/B3LYP level with the 6-31G* basis set. For N-substituted maleimide, the substituent gives only a slight influence on the maleimide chromophore, while planar conformation of PhMLH leads to the improvement in π-delocalization from substituent to maleimide unit. For 3,4-substituted maleimide, the steric repulsion between substituent and maleimide chromophore influences the extent of π-delocalization and the molecular conformation. The calculated and λem of maleimides are in good agreement with the experimental data. In the gas phase, both absorption and emission peaks are red-shift as compared to the non-substituted maleimide. Under solvent environment, the more planar conformation of PhMLH shows a blue-shift in the calculated and λem as compared with other N-substituted maleimides. For 3,4-substituted maleimides, the effect of substitution produces the most significant spectral red-shift as compared to other maleimides. 相似文献
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Optimized structures and photophysical properties of mer- and fac-Alq3 have been generated by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Investigating the substitution effect in the Alq3 derivatives, the role of the electron-donating (CH3- and NH2-) and electron-withdrawing (F-, CN-, NO2- and phenyl-) groups with 2- to 7-substitution have been analyzed. According to the calculation results, the 4- and 5- substituted Alq3 exhibit an apparent spectral shift relative to the non-substituted Alq3. The HOMO, LUMO, Eg (the energy gap between LUMO and HOMO), (maximum absorption wavelength) and f (the relative oscillator strength) of mer-Alq3 with the 4- or 5-phenyl substitution on the quinoline ligand in the ground electronic state were calculated by using the DFT/B3LYP/6-31G(d) and TD-DFT methods. 5-phenyl substituted mer-Alq3 with an electron-donating substituent showed an increase in the π-delocalization as compared to the 4-phenyl substituted mer-Alq3 derivatives. Similarly, 4-phenyl substituted mer-Alq3 with electron-withdrawing substituents also exhibits increased π-delocalization in the pyridine ring as compared to the non-substituted Alq3. Replacing the CH group at the 4, 5 and 4,5 positions of the quinoline ligand of mer-Alq3 with the aza group (nitrogen atom) gives three Alq3 analogous: AlX3, Al(NQ)3 and Al(NX)3; the calculated energy gap Eg of these derivatives decreases in the order Al(NQ)3>Al(NX)3>AX3. Four quinoline with group III metals Mq3 complexes were investigated for the photophysical properties; the calculated energy gap Eg decreases in the order Tlq3>Inq3>Gaq3>Alq3. The photophysical properties of 4-hydroxy-8-methyl-1,5-naphthyridine (mND) chelated with group III metals (MmND3 complexes) were investigated also; their calculated Eg have the opposite order as those of Mq3 complexes. 相似文献
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Chang Ken-Hao Tai Chin-Kuen Chen Likey Yeh Pao-Ling Wang Bo-Cheng 《Research on Chemical Intermediates》2019,45(1):77-90
Research on Chemical Intermediates - Six D-DPI-A (D-π-A) dyes combining various arylamine electron donors (diphenylamine and triphenylamine moieties) with a fixed π-linker (DPI) and a... 相似文献
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Chin-Kuen Tai Chun-An Hsieh Ken-Hao Chang Bo-Cheng Wang 《Research on Chemical Intermediates》2016,42(9):6907-6927
A series of D–T–A–T–D derivatives (D, electron-donating moiety; T, π-conjugated linker; A, electron-acceptor moiety) with seven electron donor moieties and various electron abilities are designed to investigate the influence of the donor on photophysical properties for small-molecule organic photovoltaic solar cells. The 4,8-dimethoxybenzodithiophene (D1), triphenyldsramine (D2), 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline (D3), 9,9-dimethyl-9H-fluorene (D4), 9-methyl-9H-carbazole (D5), 4-methyl-4H-dithieno-pyrrole (D6), and 4,4-dimethyl-4H-cyclopenta-dithiophene (D7) are adopted as the electron donor moiety. The BDTC (buta-1,3-diene-1,1,4,4-tetracarbonitrile) is used for the A moiety, and the thiophene (T) is used for the π-conjugated linker. The optimized structure of D–T–A–T–D derivatives exhibits the bend molecular conformation due to the steric effect within the A moiety. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of these derivatives are dependent on the electron donating ability of D, which influences the open-circuit voltage and driving force. Reorganization energy suggests that these derivatives are good hole-transporting type materials. Projected density of state analysis demonstrates that in the HOMO, the electron density distribution is delocalized on the terminal D and T moieties, while in the LUMO, the electron density distribution is localized mainly on the A moiety. The maximum absorption peak, which has relatively high light harvesting efficiency, is due to the π to π* transition and can be tuned by the electron-donating ability and the resonance energy of the D moiety. The bend D6–T–A–T–D6/D7–T–A–T–D7 derivatives with D moiety of 4-methyl-4H-dithieno-pyrrole (D6) and 4,4-dimethyl-4H-cyclopenta-dithiophene (D7) are good candidates as electron donor materials for SM-OPV. 相似文献
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