title: Modulation of electronic and self-assembly properties of a donor-acceptor-donor-based molecular materials via atomistic approach.
abstract: The performance of molecular materials in optoelectronic devices critically depends upon their electronic properties and solid-state structure. In this report, we have synthesized sulfur and selenium based (T4BT and T4BSe) donor-acceptor-donor (D-A-D) organic derivatives in order to understand the structure-property correlation in organic semiconductors by selectively tuning the chalcogen atom. The photophysical properties exhibit a significant alteration upon varying a single atom in the molecular structure. A joint theoretical and experimental investigation suggests that replacing sulfur with selenium significantly reduces the band gap and molar absorption coefficient because of lower electronegativity and ionization potential of selenium. Single-crystal X-ray diffraction analysis showed differences in their solid-state packing and intermolecular interactions. Subsequently, difference in the solid-state packing results variation in self-assembly. Micorstructural changes within these materials are correlated to their electrical resistance variation, investigated by conducting probe atomic force microscopy (CP-AFM) measurements. These results provide useful guidelines to understand the fundamental properties of D-A-D materials prepared by atomistic modulation.
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Joydeep
authors.initials: J
authors.lastname: Dhar
authors.forename: K
authors.initials: K
authors.lastname: Swathi
authors.forename: Durga Prasad
authors.initials: DP
authors.lastname: Karothu
authors.forename: K S
authors.initials: KS
authors.lastname: Narayan
authors.forename: Satish
authors.initials: S
authors.lastname: Patil
keywords: conductivity; electronic property; microstructure; selenium; self-assembly