Theoretical exploration of 1,3-Indanedione as electron acceptor-cum-anchoring group for designing sensitizers towards DSSC applications

•For the first time 1, 3-indanedione based electron-acceptor cum anchoring unit has been explored in designing organic sensitizers for DSSC applications.•Triphenylamine, carbazole and indoline-based electron-donors have been combined with 1, 3-indanedione based on electron-acceptor.•New design architecture, D-π-A-D has been adopted in designing organic sensitizers.•A detailed systematic DFT and TD-DFT theory level calculations have been performed.•HOMO-LUMO energy levels of all the designed dyes match well with the four-energy level system of a typical DSSC.•All computed energy levels of dyes are situated at the appropriate energy level of titania.•Simulated electronic spectra of free dyes and Dye@TiO2 extended to NIR-region.•Augmented dipole moments of adsorbed dyes attributed to the effective ICT.•Significant transfer of electron density from HOMOs to LUMOs during photoexcitation.