Exploration of optoelectronic and photovoltaic properties for azaborinine-based materials via symmetrically coupled acceptors: A DFT/TD-DFT approach

A set of azaborinine-based compounds with B-N covalent linkage (BNT1-BNT7)z, featuring an A–D–A configuration, were designed from the BNTR reference by incorporating benzothiophene (BT)-based, symmetrically coupled acceptor moieties. To determine the photovoltaic and electronic properties of the BNTR and BNT1-BNT7 compounds, density functional theory (DFT) and time-dependent DFT (TD-DFT) were utilized. Therefore, various analyses such as the frontier molecular orbitals (FMOs), binding energy (Eb), UV-Visible, density of states (DOS), open circuit voltage (Voc), transition density matrix (TDM), and electron-hole were conducted. The incorporated terminal acceptor moieties in the designed derivatives influenced their electronic properties and resulted in a narrow energy gap (ΔE = 2.611−2.450 eV). The energy gaps of each of the designated compounds were found to decrease in the following order: BNT1 > BNT3 > BNT2 > BNTR > BNT7 > BNT5 > BNT4 > BNT6. They also showed the bathochromic shifts (λmax = 617.297-650.665 nm) as compared to BNTR (623.224 nm). The BNT6 compound showed the least energy gap (2.450 eV), highest absorption (λmax =650.665 nm), and minimal binding energy value (Eb = 0.451 eV) among all derivatives. Moreover, the effective delocalization of electrons in the studied compounds was confirmed by the DOS and transition density matrix (TDM) illustrations. Furthermore, Voc was carried out in conjunction with donor (PBDB-T), and all the tailored chromophores showed reasonable results with respect to the reference compound (BNTR). Therefore, it is anticipated that the compounds under investigation will be considered attractive for the development of good organic solar cells (OSCs).