DFT Prediction of Factors Affecting the Structural Characteristics, the Transition Temperature and the Electronic Density of Some New Conjugated Polymers

Conjugated polymers are promising materials for various cutting-edge technologies, especially for organic conducting materials and in the energy field. In this work, we have synthesized a new conjugated polymer and investigated the effect of distance between bond layers, side-chain functional groups (H, Br, OH, OCH(3) and OC(2)H(5)) on structural characteristics, phase transition temperature (T), and electrical structure of C(13)H(8)OS using Density Functional Theory (DFT). The structural characteristics were determined by the shape, network constant (a, b and c), bond length (C–C, C–H, C–O, C–S, C–Br and O–H), phase transition temperatures, and the total energy (E(tot)) on a base cell. Our finding shows that the increase of layer thickness (h) of C(13)H(8)OS–H has a negligible effect on the transition temperature, while the energy bandgap (E(g)) increases from 1.646 eV to 1.675 eV. The calculation of bond length with different side chain groups was carried out for which C(13)H(8)OS–H has C–H = 1.09 Å; C(13)H(8)OS–Br has C–Br = 1.93 Å; C(13)H(8)OS–OH has C–O = 1.36 Å, O–H = 0.78 Å; C(13)H(8)OS–OCH(3) has C–O = 1.44 Å, O–H =1.10 Å; C(13)H(8)OS–OC(2)H(5) has C–O = 1.45 Å, C–C = 1.51Å, C–H = 1.10 Å. The transition temperature (T) for C(13)H(8)OS–H was 500 K < T < 562 K; C(13)H(8)OS–Br was 442 K < T < 512 K; C(13)H(8)OS–OH was 487 K < T < 543 K; C(13)H(8)OS–OCH(3) was 492 K < T < 558 K; and C(13)H(8)OS–OC(2)H(5) was 492 K < T < 572 K. The energy bandgap (E(g)) of Br is of E(g) = 1.621 eV, the doping of side chain groups H, OH, OCH(3,) and OC(2)H(5), leads to an increase of E(g) from 1.621 eV to 1.646, 1.697, 1.920, and 2.04 eV, respectively.