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Design and photoelectric properties of D-A-π-A carbazole dyes with different π-spacers and acceptors for use in solar cells: a DFT and TD-DFT investigation
- Source :
- Journal of Molecular Modeling. 25
- Publication Year :
- 2019
- Publisher :
- Springer Science and Business Media LLC, 2019.
-
Abstract
- Density functional theory (DFT) and time-dependent DFT (TD-DFT) were used to calculate the properties of the carbazole dyes TYZ-1 to TYZ-5, which differed in their π-spacers. The carbazole dyes TYZ-6 and TYZ-7 were then designed; these were based on TYZ-3 (which had 2,2′:5′,2″-terthiophene as its π-spacer) but had more strongly electron-withdrawing second acceptor groups than TYZ-3. All of these dyes except for TYZ-5 presented quasi-planar conformations, and the calculated energies of their highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) molecular orbitals as well as their HOMO-LUMO gaps (Eg) suggest that these dyes are suitable for use as sensitizers. Lengthening the π-spacer and increasing its degree of conjugation were found to cause the absorption spectrum of the dye to redshift and to facilitate hole injection. The Eg values of TYZ-6 and TYZ-7 were calculated to be smaller than that of TYZ-3 due to the weaker electron-withdrawing power of the second acceptor group in TYZ-3, and the dyes TYZ-2, TYZ-3, TYZ-6, and TYZ-7 presented the smallest Eg values. Local electron excitations following UV-vis absorption led to electronic transitions, particularly HOMO to LUMO transitions (> 94.3% of all transitions). The excited states of these dyes were found to have quasi-planar conformations, although their dihedral angles were smaller than those in the corresponding ground states. The Stokes Shifts calculated for the seven dyes (which ranged from 51.9 to 98.1 nm) suggested that self-absorption was unlikely to occur. Overall, the calculations indicated that the dyes TYZ-2, TYZ-3, TYZ-6, and TYZ-7 are promising candidates for use in dye-sensitized solar cells.
- Subjects :
- Materials science
010304 chemical physics
Absorption spectroscopy
Carbazole
Organic Chemistry
Time-dependent density functional theory
010402 general chemistry
01 natural sciences
Acceptor
Catalysis
0104 chemical sciences
Computer Science Applications
Inorganic Chemistry
chemistry.chemical_compound
Computational Theory and Mathematics
chemistry
Excited state
0103 physical sciences
Physical chemistry
Molecular orbital
Density functional theory
Physical and Theoretical Chemistry
HOMO/LUMO
Subjects
Details
- ISSN :
- 09485023 and 16102940
- Volume :
- 25
- Database :
- OpenAIRE
- Journal :
- Journal of Molecular Modeling
- Accession number :
- edsair.doi.dedup.....6e37bef4516ab4ae655a3f9bcbbd4810