The ability to use these polymers to produce organic light emitting diodes (OLEDs) and solar cells (OSCs) has created great expectations. Our neutron diffraction and quasielastic scattering experiments performed on the Osiris spectrometer are the initial stage of a program intended to investigate the structure and dynamics of the most widely used conjugated polymers –  the poly-3-alkyl-thiophenes. The added functional groups along the conducting backbone provide solubility, improving the ability to process the polymers. Nevertheless, their structure has to be controlled and their dynamics understood in order to avoid hindering the charge carrier motion that provides the basis for their usefulness in devices. We have demonstrated the coexistence of amorphous and crystalline phases, determined their melting and crystallization temperatures and provided evidence of a low temperature glass transition. This information, characterisation of the structure and dynamics at the nanoscale, is crucial to achieve the production of higher performance organic solar cells.

A Urbina, J Padilla (University of Cartagena, Spain), F Batallan, C Díaz-Paniagua (ICMM-CSIC, Spain), V García Sakai (ISIS)

Contact: Dr A Urbina, antonio.urbina@upct.es

Further reading: A Urbina et al., Phys Rev B 78 (2008) 045420