Theoretical Study of Acene-Bridged Dyes for Dye-Sensitized Solar Cells

Abstract

The electronic structures and absorption spectra for a series of acene-based organic dyes and the adsorption energy and optical properties for these dyes adsorbed on (TiO2)38 have been investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The effects of acene units and different substitution positions of electron donors on the optoelectronic properties of the acene-modified dyes are demonstrated. The photophysical properties of tetracene- and pentacene-based dyes are found to be tuned by changing the size of acene and the substitution position of the donor. The donor sites have a significant influence on the absorption wavelength mainly because of different molecular orbital (MO) contributions of the highest occupied molecular orbital (HOMO) on the bridging acene units, and the increasing MO contribution would lead to the red shift in the absorption spectra. Meanwhile, the donor is located close to the center of the π-conjugated bridge, and the absorption spectra are extended. The adsorption energy and optical properties of tetracene- and pentacene-based dyes adsorbed on (TiO2)38 suggest that acene-bridged dyes could be adsorbed on the TiO2 surface and inject electrons into semiconductors effectively. Then the results obtained from the hexacene-based dyes confirm the conclusions proposed from the tetracene- and pentence-based dyes. This study will provide a useful reference to the future design and optimization of acene dyes for dye-sensitized solar cell applications.

A DFT study on 1,4‐dihydro‐1,4‐azaborinine annulated linear polyacenes: Absorption spectra, singlet‐triplet energy gap, aromaticity, and HOMO–LUMO energy modulation

“…Majority of the aA systems show absorption in the visible region while except aT 1 , all in aT series fall in the infra‐red region. By theoretically tuning the λ max value the use of LPA mimic in dye‐sensitized solar cells can be engineered …”

Hexacene: Synthesis, Properties and Future Perspectives

“…In another example, acenes were used as the backbone of sensor dyes for the fabrication of organic sensitized solar cells. [13] It has also been proposed to contract hexacene oligomers as a new type of two-dimensional sheet-like materials. There is a rich potential for the future development of higher acenes.…”

Computational Investigation of the Influence of π‐Bridge Conjugation Order of Thiophene and Thiazole Units in Triphenylamine Based Dyes in Dye‐Sensitized Solar Cells

“…However, with this functional, sometimes the excitation energies of intramolecular charge‐transfer transition severely underestimated for large π‐conjugated systems, especially for metal‐free organic dyes for DSSCs . To check the reliability of the various functionals Li et al . carried out a theoretical investigation of excited state energies using four different functionals with three basis sets.…”