Exploration of selenophene analogue and different acceptor influence on photovoltaic properties of pyrrole-4,6(5-H)-dione based chromophores via quantum chemical investigations

Non-fullerene organic compounds are considered efficient photovoltaic materials in the development of solar cells. Therefore, considering the importance of non-fullerene organic compounds, a series of non-fullerene organic chromophores (SPF1-SPF6) was designed via molecular engineering at terminal acceptors of reference compound (SPFR). Further, owing to the interesting features of selenium than sulphur towards charge transfer, thiophene was replaced with selenophene in designed derivatives and analyzed using quantum chemical approach. Through benchmark study, CAM-B3LYP/6-311G(d, p) functional was selected for the current study. Several parameters, such as frontier molecular orbitals, density of states, binding energy, transition density matrix, optical properties, reorganization energies of electron and hole, open circuit voltage, and charge transfer analyses were assessed to comprehend the photovoltaic properties of designed compounds. A energy gap: 4.433-4.764 eV with absorption spectra as 465.1-512.7 nm in chloroform and 445.4-494.0 nm in the gas phase and greater charge transference rate was studied in selenophene derivatives. The lower E_b and the behavior of holes and electrons implied a higher rate of exciton separation and considerable transfer of charges towards LUMO from the HOMO. The results of DOS and TDM analysis further corroborated these findings. Furthermore, the V_oc, in relation to the HOMO_PTB7-LUMO_Acceptor, depicted that the proposed molecules have good V_oc values. Furthermore, a comparative study with spiro-OMeTAD, a standard hole transport material (HTM) demonstrated a good correlation, indicating that the proposed compounds have the potential to function as efficient HTMs. Therefore, it can be deduced that the use of molecular engineering with various acceptor molecules has the potential to enhance the effectiveness of photovoltaic materials.