Modification of optoelectronic properties of conjugated oligomers due to donor/acceptor functionalization: DFT study

Abstract

A comprehensive DFT study of a set of oligo(p-phenylene vinylene) molecules is performed to understand the structural and electronic changes upon functionalization. These changes are rationalized within a model considering frontier molecular orbitals of the π-conjugated system and σ-bonding orbital by which the functional group is attached to the host molecule. Two simple scalar quantum chemical descriptors are shown to correlate with optoelectronic properties of the functionalized molecule: the electronegativity and the relative electric dipole moment of the smallest π-closed shell subsystem containing the functional group and the terminal segment of the host molecule (phenyl). Both descriptors correlate linearly with the empirical Hammett σ p constant for a set of 24 functional groups. Comparison with available experimental data on UV-Vis absorption and cyclic voltammetry is made. Observed structural changes reflect changes in the electronic density.

Single Crystal Microwires of p‐DTS(FBTTh2)2 and Their Use in the Fabrication of Field‐Effect Transistors and Photodetectors

“…CAM‐B3LYP density functional is used combined with 6–31G* basis set. Among methods of the same computational complexity, this pair has been shown to provide reliable results for large π‐conjugated molecules . Electrostatic effects of a solvent are modeled by CPCM (conductor‐like polarizable continuum model) .…”

Tuning Optical Properties of Conjugated Molecules by Lewis Acids: Insights from Electronic Structure Modeling

“…The DFT-calculated N–B bond lengths (1.58–1.68 Å) and binding energies (∼100 kJ/mol) are consistent with previous experimental and theoretical values for a wide range of small LB–LA complexes (such as NH 3 :BF 3 ) reported in the literature. , We subsequently used time-dependent DFT (TD-DFT) to calculate the S 0 –S 1 transition of the adducts. Of the popular functionals we have tried, CAM-B3LYP-D3 , (thoroughly tested in our previous works) , and APFD (with incorporated dispersion correction) models show stronger correlation between calculated and experimental red shifts in the S 0 –S 1 transition. Therefore, we utilized these two methods for calculations and analysis of other properties in all of the molecules.…”

“…In the realm of electronic structure theory, prediction of structural motifs, , conformations, , and electronic features (particularly related to electronic transfer processes) − are subject to the choice of proper level of theory. For DFT, the presence of a fractional contribution of the orbital exchange is perhaps the most important parameter.…”

“…Consequently, prior to characterizing charge transfer and optical properties, we tested several commonly used functionals and basis sets to optimize the geometry of the parent molecules and adducts. To model the electrostatic effects of a solvent in all calculations, we use the conductor-like polarizable continuum model (CPCM). − , All results presented in this Letter are calculated with the 6-311G­(d,p) basis set.…”

“…To model the electrostatic effects of a solvent in all calculations, we use the conductor-like polarizable continuum model (CPCM). [41][42][43]35 All results presented in this Letter are calculated with the 6-311G(d,p) basis set.…”