Exploring the effect of oligocene elongation on photovoltaic, optoelectronic and charge transfer properties in TPA dyes tethered to the semiconductor surface

Abstract

A series of metal-free organic dyes (TPA1-TPA5) comprising triphenylamine as electron donor, cyanoacrylic acid as anchoring group and oligocenothiophene-pyrimidine as π-bridge linkers were molecularly engineered. By incorporation and elongation of oligocene spacer between donor and acceptor, electronic structures, photovoltaic and optoelectronic properties were tuned. Electronic and optical properties calculations of TPA dye upon adsorbing onto Ti 3 O 6 H and Ti 6 O 12 H were performed systematically. The charge transfer from occupied to unoccupied molecular orbitals in unaccompanied dyes and TPA@TiO 2 clusters, broad and long range spectral peaks affirmed that linkers elongation enhance electron injection (ΔG inject ) and electronic coupling constants (|V RP |). Tailoring the energy gap by elevating HOMO and lowering LUMO energy levels as well as fostering ΔG inject , oligocene elongation was commenced excellent linkers. The superior photovoltaic parameters than referenced compounds, frontier molecular orbitals analyses and charge transfer nature in TPA@TiO 2 clusters are illuminating that these dyes would be efficient to be used in photovoltaic devices.