New Thiophene-Linked Conjugated Poly(azomethine)s:  Theoretical Electronic Structure, Synthesis, and Properties

Abstract

We report a joint theoretical and experimental study of several new thiophene-based poly(azomethine)s. Hybrid density functional theory (DFT) method was used to calculate the optimized geometry and electronic structure of poly(azomethine)s. Theoretical band gaps of the new thiophene-based poly(azomethine)s were in the range 2.33−2.67 eV, which are smaller than that of the phenylene-based polymer. The variation of the backbone ring (fluorene, carbazole, or naphthalene) or donor/acceptor side group on the phenylene ring significantly affected the dihedral angles and resulted in the variation of electronic properties (ionization potential, electron affinity, and band gap) of the poly(azomethine)s. Five soluble new conjugated poly(azomethine)s derived from the polymerization of 2,5-diformyl-3-hexylthiophene (DFHT) with various diamines were prepared and characterized. The optical and electrochemical band gaps of the polymer films were in the ranges 2.21−2.28 and 2.13−2.24 eV, respectively. The trend of the effect of the backbone ring or side chain on the experimental electronic properties is in good agreement with the theoretical results. Our study demonstrates how the electronic properties of conjugated poly(azomethine)s can be tuned by the backbone ring or side group, which could be important for electronic or optoelectronic applications of the materials.

Quantum chemical investigations aimed at modeling highly efficient zinc porphyrin dye sensitized solar cells

“…Density functional theory (DFT) is well known to be suitable for calculating the chemical and structural properties of species, such as organic semiconductors, optoelectronics, and conventional inorganic semiconductors [24][25][26][27][28][29][30][31]. Electronic properties of carbon nanotubes and graphene nanoribbons have been investigated using the Heyd −Scuseria−Ernzerhof (HSE) screened exchange hybrid and the hybrid meta-generalized functional of Tao, Perdew, Staroverov, and Scuseria (TPSSh).…”

Tuning of the photophysical and electrochemical properties of symmetric and asymmetric conjugated thiophenoazomethines

“…25,26 Considering that the tuning of the HOMO-LUMO energy gap exerts a great inuence on optoelectronic properties, solid-state and charge-transport characteristics of molecular devices, we become interested in the incorporation of different groups into the thiopheneazomethines and then synthesizing the corresponding symmetric and asymmetric thiophenoazomethines and evaluating their effect on the photophysical and electrochemical properties. This research provides crucial information for the future design and synthesis of all-thiopheneazomethines with desired characteristics.…”

Poly(diphenylacetylene)s with Electron‐Donating Alkoxy and Electron‐Withdrawing Fluoroalkyl Groups: Effect of the Substituent on Fluorescence

“…[7][8][9][10][11][12][13][14] Whether to attach an electron-donating or an electron-withdrawing group to the main chain is very important in relation to fluorescence-color tuning, efficient exciton confinement, and carrier-transporting performance as well as for the improvement of the solubility and processability of the polymers: their HOMO/LUMO energy levels and the band gap energy can be optimized in the desired direction by the incorporation of such substituents. Disubstituted acetylene polymers exhibit intense photoluminescence, while the corresponding monosubstituted acetylene polymers show weak luminescence, except for some examples.…”