We propose, as a solution to seek more efficient OPVs and reduce production costs, the exploitation of discotic liquid crystalline (LC)
phases as alternative acceptors to fullerenes.
Discotic LCs are excellent candidates for OPVs due to their good absorptivity in the visible spectrum and for being homeotropically aligned by annealing and surface effects. The LC phases will be designed to combine favourable characteristics, namely: high absorptivity where the solar emission is more intense, electron-acceptor character relative to poly(alkylthiophene)s, and ability to assemble in nanostructures with enhanced charge mobility. To ensure the morphological stability of the resulting LC supramolecular structures, they will be synthesised as cross-linkable materials.
We will deal with two classes of disc-like materials, both recognized as good electron acceptors, and with tunable LUMO levels, from which new
materials with LC properties will be derivatized: electron acceptors from the class of fluorenes (Fs) and the N,N´-Dicyanoquinone Diimines
(DCNQIs). Whereas DCNQIs have only been explored as crystalline conductive salts, electron-acceptors from the Fs class have never been
prepared as liquid crystal materials.
Our workplan includes: i) screening among known DCNQIs and Fs and selection of those with more favourable photophysical and electron-acceptor character in relation to poly(alkylthiophene)s; ii) synthesis of new LC materials as derivatives of those exhibiting more promising properties; iii) investigation of their self assembly character and development of methodologies to build film morphologies including the donor component; iv) characterisation of the active layers in terms of photophysical properties; v) fabrication and characterisation of OPV cells.
|Start Date: 01-05-2013
|End Date: 01-04-2015
|Team: Ana Maria de Matos Charas, Jorge Manuel Ferreira Morgado, Manuel Jose de Matos
|Groups: Organic Electronics – Lx
|Local Coordinator: Ana Maria de Matos Charas
|Links: Internal Page