Exploring Photo-Physical Properties of Tetramethyl Silolo Dithiophene-Based Derivatives by DFT Approach: Influence of Acceptor Moieties

To achieve the rising demand of photovoltaic materials, a series of small non-fullerene chromophores (TMS1-TMS7) with A-π-D-π-A architecture were designed via structural modulation of reference compound (TMSR) by incorporating terminal acceptors. Density functional theory (DFT) and time-dependent DFT (TD-DFT) analyses were computed at M06/6–311G (d,p) level to explore opto-electronic characteristics of the aforementioned derivatives. Frontier molecular orbitals (FMOs), density of states (DOS), absorption maxima (λmax), transition density matrix (TDMs), open-circuit voltage (Voc), and electron hole analyses were performed to comprehend photovoltaic response. Energy gap reduction was found in the range of ΔE = 2.631 to 1.813 eV with enhanced absorption ranging from 584.03 to 832.16 nm in solvent chloroform. Similarly, global reactivity parameters (GRPs) were conducted utilizing HOMO and LUMO energies. Moreover, Voc was performed in conjunction with polymeric donor PCBM and all tailored compounds show reasonable results with respect to reference compound. Interestingly, among all chromophores, TMS7 was noted with the lowest energy gap (1.813 eV), maximum λmax (832.165 nm) and remarkable efficiency, demonstrating promising photovoltaic response. This work revealed that designed compounds may appropriate for promising organic photovoltaics (OPVs) material.