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

Abstract

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, OCH₃ and OC₂H₅) on structural characteristics, phase transition temperature (T), and electrical structure of C₁₃H₈OS 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 C₁₃H₈OS-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 C₁₃H₈OS-H has C-H = 1.09 Å; C₁₃H₈OS-Br has C-Br = 1.93 Å; C₁₃H₈OS-OH has C-O = 1.36 Å, O-H = 0.78 Å; C₁₃H₈OS-OCH₃ has C-O = 1.44 Å, O-H =1.10 Å; C₁₃H₈OS-OC₂H₅ has C-O = 1.45 Å, C-C = 1.51Å, C-H = 1.10 Å. The transition temperature (T) for C₁₃H₈OS-H was 500 K < T < 562 K; C₁₃H₈OS-Br was 442 K < T < 512 K; C₁₃H₈OS-OH was 487 K < T < 543 K; C₁₃H₈OS-OCH₃ was 492 K < T < 558 K; and C₁₃H₈OS-OC₂H₅ 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 OC₂H₅, leads to an increase of E_g from 1.621 eV to 1.646, 1.697, 1.920, and 2.04 eV, respectively.

Keywords: bond length; conjugated polymers; density functional theory; transition temperatures.

Scheme 1

The synthetic procedure of poly(C₁₃H₈OS–X), X is H, Br, OH, CH₃, C₂H₅.

Figure 1

System energy (a), electronic density (b), electronic state (c) of poly(C₁₃H₈OS–H) with a different number of steps.

Figure 2

The quantities characteristic of the structure, and electronic structure of poly(C₁₃H₈OS–H) materials such as Shape (a), phase transition temperature zone (b), electronic structure (c), and the density of states (d).

Figure 3

The electronic density in the chemotherapy band.

Figure 4

The electronic structures of poly(C₁₃H₈OS–H) (a), poly(C₁₃H₈OS–Br) (b), poly(C₁₃H₈OS–OH) (c), poly(C₁₃H₈OS–OCH₃) (d), and poly(C₁₃H₈OS–OC₂H₅) (e), E_g of poly with different impurities (f).

Figure 4

The electronic structures of poly(C₁₃H₈OS–H) (a), poly(C₁₃H₈OS–Br) (b), poly(C₁₃H₈OS–OH) (c), poly(C₁₃H₈OS–OCH₃) (d), and poly(C₁₃H₈OS–OC₂H₅) (e), E_g of poly with different impurities (f).

Figure 5

The structural shapes of C₁₃H₈OS–H (a), C₁₃H₈OS–Br (b), C₁₃H₈OS–OH (c), C₁₃H₈OS–OCH₃ (d), C₁₃H₈OS–OC₂H₅ (e), and the electronic energies structures with poly different (f).