The impact of structural modifications into benzodithiophene compounds on electronic and optical properties for organic solar cells

To meet the energy demands, fullerene-free organic systems have been emerging as efficient photovoltaic ma-terials. Therefore, we have tailored benzodithiophene-based A-& pi;-D-& pi;-A configured, MBT1-MBT9 derivatives after end-capped modifications in MBTR. A comparative study between theoretical & lambda;maxvalues of MBTR at different levels of density functional theory (DFT) and experimental was executed in order to select appropriate functional for current study. Owing to the close harmony between the results of M06/6-311G(d,p) level and experimental findings, the aforesaid function/basis set was selected for the further investigation. Different analyses such as binding energy (Eb), transition density matrix (TDM), global reactivity parameters (GRP), open-circuit voltage (Voc), optical properties (UV-Vis), hole electron and frontier molecular orbital (FMO) energies, were computed to probe the photovoltaic properties of MBTR and MBT1-MBT9. The addition of different acceptors in MBT1-MBT9, lessen the energy gap (& UDelta;E = 2.362-2.000 eV) along with the increase in bathochromic shift (& lambda;max = 651.657-766.672 nm) compared to the reference chromophore (& UDelta;E = 2.672 eV and & lambda;max = 585.466 nm). In addition, FMO findings revealed the significant charge transference from HOMO towards LUMO, which were further supported by TDM maps. Interestingly, all the tailored molecules exhibit low Eb (0.459-0.383 eV), which indicates the higher exciton dissociation in MBT1-MBT9. Comparable results of Voc for MBT1-MBT9 and MBTR were obtained via HOMOPBDBT-LUMO Acceptor. Among all the derivatives, due to least band gap, wider ab-sorption spectrum and lower Eb along with higher exciton dissociation rate in MBT9, excellent photovoltaic properties were examined in this derivative. All these analyses support conceptualized compounds as efficient photovoltaic materials and encourages the experimentalists to synthesize these compounds to obtain proficient photovoltaic materials.