Synthesis of a Novel D-A Type Photoelectrical Material: 5,5'-(9,9-Dioctyl-9H-Fluorene-2,7-Diyl)bis(Thiophene-2-Carbaldehyde)

Abstract

A donor-acceptor organic molecule based on fluorene unit as an electron donor and aldehyde group as an electron acceptor has been demonstrated in high yields over four steps. This approach offers a much milder and more efficient route to synthesize the target compound via the Vilsmeier-Haack reaction. Optical spectra show that the electron-accepting groups induce an intermolecular charge transfer, resulting in a shift of the absorbance maximum toward longer wavelength. Such D-A type intermediate compounds as organic molecules display a significantly improved property profile in photoelectrical materials for applications in organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), and organic field-effect transistors (OFETs).