Journal
JOURNAL OF CHEMICAL PHYSICS
Volume 156, Issue 17, Pages -Publisher
AIP Publishing
DOI: 10.1063/5.0092880
Keywords
-
Funding
- NSFCs [22133001, 21773252, 21827803]
- Project for high-grade, precision and advance in Beijing (BUPT)
Ask authors/readers for more resources
Understanding the charge transfer/separation processes in donor-pi-acceptor chromophores is important for improving the performance of dye-sensitized solar cells. In this study, two newly synthesized molecules, CS-14 and CS-15, were investigated for their intramolecular charge transfer dynamics. The results showed that the CT/CS characters of the dyes were influenced by solvent polarity. CS-15 exhibited better planarization and slower charge recombination, leading to higher charge migration efficiency in DSSCs.
Understanding the excited-state charge transfer/separation (CT/CS) of donor-pi-acceptor chromophores can provide guidance for designing and synthesizing advanced dyes to improve the performance of dye-sensitized solar cells (DSSCs) in practical applications. Herein, two newly synthesized electronic push-pull molecules, CS-14 and CS-15, that consist of carbazole donor and benzothiadiazole acceptor segments are chosen to explore the ultrafast dynamics of intramolecular CT/CS processes. The theoretical calculation results depict an excited-state intramolecular CT character for both dyes, while the dihedral angle between donor and acceptor of CS-14 is larger than that of CS-15, suggesting a more significant CT character of CS-14. Furthermore, compared to CS-14, the bond rotation of CS-15 between donor and pi-bridge is restricted by employing the hexatomic ring, indicating the stronger molecular planarization of CS-15. Ultrafast spectroscopy clearly shows a solvent polarity-dependent excited-state species evolution from CT to CS-the CT character is observed in low-polar toluene solvent, while the feature of the CS state in polar tetrahydrofuran and acetone solvents is captured, which successfully proved a solvent polarity modulated excited-state CT/CS characters. We also found that though the generation of the CS state within CS-14 is slightly faster than that of CS-15, the charge recombination process of CS-15 with excellent planar conformation is much slower, providing enough time for a higher charge migration efficiency in DSSCs. Published under an exclusive license by AIP Publishing.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available