Journal of Molecular Modeling

, Volume 19, Issue 12, pp 5317–5325

Structure-property relationships for three indoline dyes used in dye-sensitized solar cells: TDDFT study of visible absorption and photoinduced charge-transfer processes

Original Paper

DOI: 10.1007/s00894-013-2024-4

Cite this article as:
Li, H. & Chen, M. J Mol Model (2013) 19: 5317. doi:10.1007/s00894-013-2024-4

Abstract

The electronic structures of three D-A-π-A indoline dyes (WS-2, WS-6, and WS-11) used in dye-sensitized solar cells (DSSCs) were studied by performing quantum chemistry calculations. The coplanarity of the A-π-A segment and distinct noncoplanarity of the indoline donor part of each dye were confirmed by checking the calculated geometric parameters. The relationships between molecular modifications and the optical properties of the dyes were derived in terms of the partial density of states, absorption spectrum, frontier molecular orbital, and excited-state charge transfer. 3D real-space analysis of the transition density (TD) and charge difference density (CDD) was also performed to further investigate the excited-state features of the molecular systems, as they provide visualized physical pictures of the charge separation and transfer. It was found that modifying the alkyl chain of the bridge unit near the acceptor unit is an efficient way to decrease dye aggregation and improve DSSC efficiency. Inserting a hexylthiophene group next to the donor unit leads to a complicated molecular structure and a decrease in the charge-transfer ability of the system, which has an unfavorable impact on DSSC performance.

Keywords

Dye-sensitized solar cellOrganic sensitizerTDDFTAbsorption spectrumCharge transferCharge difference density

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.School of Physics and Optoelectronic Technology, and College of Advanced Science and TechnologyDalian University of TechnologyDalianPeople’s Republic of China