Module 7: Organic Semiconductors (PHY6007)
Molecular materials can now be synthesised with useful electronic and photonic properties. Harnessing these materials will deliver a revolution in the electronics industry.
Above: Fluorescence of polymers and polymer additives.
Electronic and photonic molecular materials and devices are one of the most promising new areas of solid state research, encompassing materials chemistry, device physics and electrical engineering. Molecular materials will revolutionise the display industry and create the new market of 'disposable electronics'.
This module will introduce students to a science that is not yet part of the standard syllabus of its 'parent' disciplines.
Outline syllabus
- Molecular materials: definitions, examples, hybridisation, conjugation, excitations.
- Characterisation techniques: spectroscopies, electrochemistry, current-voltage measurements.
- Materials types: Molecular crystals, conducting vs semiconducting polymers.
- Applications I: plastic conductors, polymer batteries, electro/photochromism.
- Applications II: xerography, LEDs, FETs, lasers.
- Organic electroluminescent displays: injection, transport, Exciton formation, light emission.
- Influence of supramolecular order: excimers, H- and J-aggregates, liquid crystallinity.
Above: Photograph of an organic LED in the test bed.
Teaching objectives
This module will enable students to:
- understand basic properties of molecular materials, provide examples, and discuss their applications.
- understand the physics of organic LEDs, photodiodes, FETs, optical amplifiers and lasers.
- appreciate the influence of supramolecular structure on their performance in devices.
- understand the issues concerning device fabrication, like multilayer architectures, patterning and encapsulation.
Coursework and assessment
In addition to the lectures, small groups will be assigned to the study of a special topic in-depth beyond the coverage in the lecture. Typical examples will be organic photovoltaics, molecular recognition with crown ethers, or the technique of cyclic voltammetry. The deliverable elements of this coursework are a joint oral presentation to the full class and a written essay, both of which will be marked. In addition, students will sit a written multiple choice exam. Also, practical laboratory experiments will be organized jointly between all Sheffield modules.
Recommended reading
- M C Petty, M R Bryce, D Bloor (eds.), 'Introduction to Molecular Electronics', Edward Arnold, London, 1995 (ISBN 0-340-58009-7)
- G Hadziioannou, P F van Hutten, 'Semiconducting Polymers: Chemistry, Physics, and Engineering', Wiley-VCH, 2000 (ISBN 3-527-29507-0)
- R H Friend et al, Nature Vol. 397, 121 (1999)
- A Kraft, A C Grimsdale, A B Holmes, Angew. Chem. Int. Ed. Vol. 37, 403 (1998)
- D D C Bradley, Current Opinion in Solid State & Materials Science Vol. 1, 789 (1996)
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