The development of polymer-based optoelectronic devices (or ‘plastic solar cells’) that could deliver electricity at a competitive cost is a key area of research. Solutions of conjugated polymers can be ‘printed’ to produce the active layer of low-cost solar cells by means of technologies such as screen and ink-jet printing or spray coating.
The properties of this ‘ink’ need to be controlled to ensure that the self-assembled nanostructures formed in the process are electrically conducting. Small angle neutron scattering (SANS) measurements were made on LOQ on a range of solutions of conjugated pure and blended polymers at different temperatures. From these studies, we are able to determine how solvent interaction, temperature, polymer molecular weight, and polydispersity influence the structural properties of the polymer assemblies in solution. A temperature-induced shape change (from globular to semi-flexible rod) and solvent-induced size changes have been observed. These findings will be used to improve the layer fabrication procedure which, in turn, will increase the efficiency of the resulting solar-cell.
A Urbina, N Espinosa, R García-Valverde (Universidad Politécnica de Cartagena, Spain), V García-Sakai, SE Rogers (ISIS), F Batallan, C Díaz-Paniagua (Instituto de Ciencia de Materiales, Spain), M Jiménez (ILL, France), J Abad (Universidad de Murcia, Spain)
Research date: January 2010
Contact: Dr A Urbina, email@example.com
Further reading: A Urbina et al., Phys Rev B 78 (2008) 045420; R García-Valverde et al., Prog Photovolt: Res Appl 18 (2010) 535