Molecular engineering of near-infrared active boron dipyrromethene moiety with various donors and acceptors for tuning the absorption behavior and electron injection of the resultant dyes

Small molecules having an absorption band beyond 750 nm for DSSC applications are scarce in the literature. Derivatives of boron dipyrromethane (BODIPY) are popular fluorophores in life sciences and hence used in fluorescent microscopy for staining different intracellular organelles, and BODIPY-based dye molecules have been known for the strong absorption in the visible and near IR regions. A series of twelve (Donor-π-linker)2-Ancillary Acceptor-Acceptor ((D-π)2-An-A)) based metal-free organic dyes comprising BODIPY moiety as an ancillary acceptor (An) were designed to fine-tune the panchromatic behavior of BODIPY dyes. Based on the density-functional theory (DFT) and time-dependent DFT, the photophysical and photoelectrochemical properties of the dyes were investigated. To convey the objective of the work, several photovoltaic parameters, such as dye regeneration driving force (ΔGreg), reorganization energy (Λ), chemical reactivity parameters, dye adsorption energy (Eads), and the density of states were calculated to justify the suitability of the dyes for the DSSCs application. This study identified six dyes with carbazole and phenothiazine-based donors as DSSC suitable panchromatic dyes.