Theoretical Approach to the Study of Thiophene-Based Discotic Systems As Organic Semiconductors

Abstract

The main parameters that control charge transport at the molecular level have been studied for a series of columnar mesophase, thiophene-based discotic systems at semiempirical and DFT levels using different approximations, i.e., the dimer model and isolated molecule calculations. Charge carrier mobility was estimated through the charge transfer constant evaluated according to the semiclassical Marcus theory and compared to that obtained for a reference compound, i.e., triphenylene derivative. A set of different density functionals has been essayed in order to search for general patterns for charge transport related properties. In summary, only the compound with four thiophene rings, RO-TetraT, shows a significant increase in p character in comparison to the triphenylene derivative.

Theoretical Investigation on Charge Transfer Properties of 1,3,5-Tripyrrolebenzene (TPB) and its Derivatives with Electron-withdrawing Substituents

“…[32] Actually, the Heff heavily depends on the relative packing and only the nearest or the best face to face dimers which contribute the most effective charge transport were taken into account in evaluating μ in many works. [33] According to Einstein relation, charge mobility (μ) can be evaluated by [34,35] :…”

Theoretical studies on charge transport and optical properties of tris(N-saclicylideneanilines)

“…Charge transport studies on the different types of discotic liquid crystalline molecules, such as triphenylenes, polycyclic aromatic hydrocarbons, and perylene diimide, show that these molecules exhibit high charge carrier mobility and their values range between 0.002-1.3 cm 2 V À1 s À1 . [7][8][9] Although a number of experimental and theoretical investigations have been performed on liquid crystalline materials 4,6,[10][11][12][13] and organic semiconductors, [14][15][16] it is necessary to investigate the charge transport and optical properties of newly synthesized molecules to improve the performance of the organic semiconducting materials by modifying the structure through the substitution of functional groups and side chains.…”

Alkylated Benzodithienoquinolizinium Salts as Possible Non-Fullerene Organic N-Type Semiconductors: An Experimental and Theoretical Study

“…In line with other theoretical studies [ 55 ] that not only shed light on their properties, but also help identify new interesting compounds by comparing their properties with those of known materials, we investigate in the present communication the properties of polycyclic pyridinium salts as candidates for the development of n-type organic semiconductors. Besides their electron-deficient character and their potential ability to form columnar aggregates, other structural features were included in their synthesis, which were above-mentioned as leading to better n-type organic semiconductors.…”

“…Charge mobility is an important factor to be considered in organic semiconductors. Transport properties are commonly discussed with the aid of Marcus theory [ 55 ], though other approaches are also found in the literature [ 72 , 73 , 74 , 75 , 76 , 77 , 78 ].…”

“…Having assumed the two parallel alignments for our cationic dimers, we estimated the charge transport in these discotic systems employing the Marcus theory [ 55 , 79 , 80 ] and Einstein’s equation for a one-dimensional diffusion process [ 81 , 82 ].…”