4. Conclusion
An insight into the optical and electronic properties of twelve
synthetic and four designated DTS compounds have been fully
researched in this paper. By using means of DFT and TD-DFT theoretically
specific calculations, the most crucial outcomes can be concluded as
follow:
- The distinctions from optimized structures among the four forms
(neutral, anion, cation, S1) of DTS and its derivatives and between
symmetric and asymmetric groups have a direct influence on electronic
properties of the studied molecules.
- Two phenyl groups substituted at silyl atoms, as well as functional
groups at 1,1’-positions are reasonable for the changes in the optical
and electronic properties of DTS compounds.
- The introduction of pyridyl groups is seen as a positive signal. For
example, to make a lowered LUMO level and optical band energies, and
to increase the charge transport rate.
- Of optical analysis, the UV spectra of the derivatives 1-11generally involved in the phenomenon of red shift with respects to
parent molecule DTS . Furthermore, the increase of
π-conjugated units not only make a good strategy to scale down the
band gap, but it also improves the useful application of DTS typical
dimer in emissive materials.
- Among studied compounds, the dimeric compound could be seen as the
good candidate for applying in organic electron transport OLED layer.
- By substituting the functional groups at 1,1’-positions of DTS dimeric
compound 10 , we successfully make changes in the charge
transport rate of the designated compounds 10a-10d ,
especially the remarkable reduction in hole reorganization energies
which has been improved.
We believe that this paper would make a contribution to the
understanding of the optoelectronic values of dithienosiloles. Worthy
experimental investigations based on DTS-type are expected.
Supplementary materials Figs. S1-S3 and Table S1-S2.
Acknowledgments This work was supported by a grant, No.
VAST.CTG.01/17-19 from Vietnam Academy of Science and Technology (VAST),
18 Hoang Quoc Viet, Caugiay, Hanoi, Vietnam.
Conflict of Interest The authors declare no conflict of
interest.