DFT Study of Polythiophene Energy Band Gap and Substitution Effects

Abstract

Polythiophene (PTh) and its derivatives are polymer-based materials with aπ-conjugation framework. PTh is a useful photoelectric material and can be used in organic semiconductor devices, such as PLED, OLED, and solar cells. Their properties are based on molecular structure; the derivatives contain different substitutes in the 3 and 5 positions, such as electron-donating or electron-withdrawing groups. All molecular geometries were optimized at B3LYP/6-31G(d,p) level of theory. The energy gap (Egap) between the HOMO and LUMO levels is related to theπ-conjugation in the PTh polymer backbone. In this study, the DFT calculations were performed for the nonsubstituted and 3,5-substituted variants to investigate the stability geometries and electrical properties. The theoretical calculations show that the substituted forms are stable, have lowEgap, and are in good agreement with the experimental observations.

Iodo-Bridged Transition States; New Mechanistic Pathways for Base-Catalyzed Halogen Dance

“…Computations are all done at DFT-Cam-B3LYP/ lanl2dz level of theory [27][28][29], using Gaussian g09 package [30,31]. Based on similar reports dealing with halogens Cam-B3LYP method is accurate and precise enough to address the problem at hand [32][33][34][35].…”

Mechanism of Base-Catalyzed Halogen Dance Reactions and the Role of Bromo-Bridged Transition States

“…All computations were done at DFT-Cam-B3LYP/ lanl2dz level of theory [11][12][13][14][15][16][17] , using gaussian g09 package [18][19][20] , the reliability of basis set is already proven to yield very similar to results obtained with CCSDT coupled cluster configurational methods [21][22][23][24][25][26] , in particular for halogens and their long-range contact be it of parallel or orthogonal X---X interactions. The choice of DFT-Cam-B3LYP/ lanl2dz level of theory is mainly based on the reliable reproducible TS structures that are consistent with regard to the dihedral between the two benzene rings in their structure.…”

Electrospun Polyacrylonitrile/Polythiophene Fibers for Phosphate Anion Sensing

“…Polythiophene (PTh) is an important member of the family inherently conducting polymer (Kaloni et al, 2017). PTh has been widely studied for use in light-emitting diodes, water purification devices, molecular electronics, hydrogen storage, biosensors, and optoelectronic devices (Bouzzine et al, 2015;Kaloni et al, 2017). Generally, PTh and its derivatives are obtained by chemical oxidation and electrochemical synthesis (Bouzzine et al, 2015;Massoumi et al, 2016).…”

“…PTh has been widely studied for use in light-emitting diodes, water purification devices, molecular electronics, hydrogen storage, biosensors, and optoelectronic devices (Bouzzine et al, 2015;Kaloni et al, 2017). Generally, PTh and its derivatives are obtained by chemical oxidation and electrochemical synthesis (Bouzzine et al, 2015;Massoumi et al, 2016). However, few studies focused on studying the electrochemical properties of PTh nanofibers (Ambade et al, 2017).…”