abstract
Polyfluorene copolymers are functionalised with oxetane side groups which make them cross-linkable upon exposure to an acid. Upon addition of a photoacid they become photo-cross-linkable if exposed to UV light. Optical and electrochemical properties of these copolymers, both in the soluble and crosslinked forms are compared. We further show that the use of this type of copolymer allows the fabrication of multilayer structures without restriction of the organic solvent used to deposit an upper layer. In particular, we fabricate multilayer LEDs with enhanced luminous efficiency using one of the copolymers. The possibility to photo-cross-link these materials is also used to prepare micrometer size patterns, using a transmission electron microscope grid as a shadow mask. Furthermore, the use of a scanning near-field optical microscope allows submicron patterns to be prepared. We propose that this approach, which can be extended to a wide range of conjugated polymers, can be useful for the fabrication of optical, electronic and optoelectronic structures.
keywords
LIGHT-EMITTING-DIODES; FIELD OPTICAL LITHOGRAPHY; FLUORENE-BASED COPOLYMERS; ELECTROLUMINESCENT DEVICES; LUMINESCENCE PROPERTIES; CONJUGATED COPOLYMERS; POLYMERS; TRANSPORT; EFFICIENT; POLYACETYLENES
subject category
Materials Science; Physics; Polymer Science
authors
Charas, A; Alves, H; Martinho, JMG; Alcacer, L; Fenwick, O; Cacialli, F; Morgado, J
our authors
Helena Alves
Principal Researcheracknowledgements
This work was partially supported by FCT-Portugal and FEDER under the contract no. POCTI/CTM/40063/2001. HA thanks FCT for a post-doctoral grant. The collaboration between IST and UCL was partially supported by a British Council/CRUP bilateral agreement. We also thank the Royal Society and the European Commission (THREADMILL-MRTN-CT-2006-036040) for financial support. This work, as part of the European Science Foundation EUROCORES Programme SONS, was also supported from funds by the EPSRC and the EC Sixth Framework Programme, under contract N. ERAS-CT2003-980409-Supramates.