title: Organic donor-acceptor assemblies form coaxial p-n heterojunctions with high photoconductivity.
abstract: The formation of coaxial p-n heterojunctions by mesoscale alignment of self-sorted donor and acceptor molecules, important to achieve high photocurrent generation in organic semiconductor-based assemblies, remains a challenging topic. Herein, we show that mixing a p-type π gelator (TTV) with an n-type semiconductor (PBI) results in the formation of self-sorted fibers which are coaxially aligned to form interfacial p-n heterojunctions. UV/Vis absorption spectroscopy, powder X-ray diffraction studies, atomic force microscopy, and Kelvin-probe force microscopy revealed an initial self-sorting at the molecular level and a subsequent mesoscale self-assembly of the resulted supramolecular fibers leading to coaxially aligned p-n heterojunctions. A flash photolysis time-resolved microwave conductivity (FP-TRMC) study revealed a 12-fold enhancement in the anisotropic photoconductivity of TTV/PBI coaxial fibers when compared to the individual assemblies of the donor/acceptor molecules.
authors.affiliation: Photosciences and Photonics Group, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum-695019 (India).
authors.forename: Seelam
authors.initials: S
authors.lastname: Prasanthkumar
authors.forename: Samrat
authors.initials: S
authors.lastname: Ghosh
authors.forename: Vijayakumar C
authors.initials: VC
authors.lastname: Nair
authors.forename: Akinori
authors.initials: A
authors.lastname: Saeki
authors.forename: Shu
authors.initials: S
authors.lastname: Seki
authors.forename: Ayyappanpillai
authors.initials: A
authors.lastname: Ajayaghosh
keywords: donor-acceptor systems; p-n heterojunctions; photoconductivity; self-assembly; self-sorting