Towards Type IV Metallopolymers for Fast Organic Electronics

Organic materials chemists have been attempting for decades to build organic based electronics and photovoltaics that can match, or outperform, the traditional standard of inorganic construction. In general, it is now becoming increasingly recognized that there is a greater advantage that arises from mixing inorganic and organic components to achieve desired materials properties. Such hybrid systems benefit from a variety of synergistic effects, including, greater thermal stability and processability. Of late, the field of organic metallopolymers has expanded greatly due to innovations in methodology and characterization. New and powerful functional materials that meet many of the property and practical requirements have resulted. However, in the field of semi-conductors the materials have been limited to slow electronic processes due to the naturally increased band gaps introduced by the organic component. This imperfect redox matching between the metal and polymer backbone can be fatal to the final materials properties and thus redox matching consumes the bulk of efforts in this field. To solve this limiting problem a dramatically new approach will be investigated. In this approach, dense-metal metallopolymers with proximal and intimately electronically coupled metals will be targeted. Since the metals rely less on the organic ligands to 'talk' to each other, unhindered charge and energy transport in these systems will become available. Such systems will lead to a giant leap in fast and efficient organic electronics. Moreover, the proposed materials will be prepared using efficient synthetic reactions and versatile building blocks from both the covalent and non-covalent perspectives. The final materials will be at once, electron accepting, highly conductive and fully property tunable.

General Impact:

In the short-term, the proposed work will be primarily academic in that it will focus on proof-of-principle studies and fundamentals. This framework is realistic within the time period covered by the EPSRC First Grant Scheme. The immediate impact will be to further our collective understanding of organic-based fast electronics.

Departmental Impact:

The work presented herein will build the chemical synthesis credentials of the Department, allow direct communication between physicists and chemists, foster multidisciplinary training and research, synergize new directions of study and substantially increase the Department's breadth of research.

Chemistry Impact:

The proposed project is topical and cutting edge in chemistry. Resulting papers will attract high profile citations and will have dramatic impact on the direction of the fields of study involved. Firstly, the use of predominantly triazole-based materials for optoelectronics is only now coming to the fore and initial results are highly promising. Secondly, the use of fast and efficient reactions towards new materials is an important effort in chemistry (e.g. dial-a-molecule) and the addition herein of a supramolecular aspect further enhances this concept. Thirdly, palladium and platinum chemistry, the metals most employed in this proposal, is in an accelerated state of development.

Physics Impact:

The research will also deliver new materials suitable for fundamental studies of electron and energy transfer that will intrigue the broader community of solid-state and condensed-matter physicists developing new, and utilizing established, methods in time-resolved spectroscopy. The study of the dynamics of excitons and polarons, for example, in highly conductive hybrid inorganic/organic systems would represent an important and timely research effort. Fast electronics in organic systems is anticipated to be a central future technology. Platinum-based materials are becoming increasingly important in applications in organic light emitting diodes and the underlying processes are hot topics in physics.

Engineering Impact:

The final materials will be intricately designed, fully tunable and will be available on a built-to-order basis through a combination of highly controllable covalent and non-covalent chemical techniques. The successful completion of this work will have ramifications in a number of important device areas with industrial activity including photovoltaics, nonlinear optics, organic field effect transistors and organic light emitting diodes. OFET structures will be studied directly after this two year program of research to establish electron mobilities and also to identify specific applications suitable for these molecules based on various device parameters.