Year

2003

Degree Name

Doctor of Philosophy

Department

Department of Chemistry

Abstract

The development of new materials has greatly expanded the application of energy conversion technologies. Conducting electroactive polymers, such as polypyrrole and polythiophenes, containing specific groups represent a new class of electroactive semiconducting materials with great potential application in a number of areas, including hydrogen gas generation and photovoltaic devices.

A range of novel conducting electroactive polymers have been synthesized and characterized in this work. A new electrolytic cell system for hydrogen gas generation and a new solar cell system for photovoltaic (energy conversion from sunlight to electricity) applications have been devised.

Conducting electroactive polymers, polypyrrole and polythiophene, containing pendant group ferrocene or ferrocenophane have been electrochemically synthesized for hydrogen gas generation. Electrochemically controlled hydrogen production has been carried out with these new ferrocene or ferrocenophane containing polymer-modified platinum electrodes. Results show that these coatings catalyze hydrogen gas generation, which is associated with the presence of the ferrocene or ferrocenophane moiety in the conducting electroactive polymers. A significant and substantial anodic shift occurs in the potential for formation of hydrogen gas when using these polymer-modified platinum electrodes. In addition, the basicity of the ferrocene moiety and the porosity and the morphology of the conducting polymer have been shown to play significant roles in the rate of potentiostatic hydrogen gas generation.

Photovoltaic devices have also been fabricated by using novel conducting electroactive polymers electrosynthesised from bis-linked terthiophene and porphyrin substituted bisterthiophene as light harvesters. The electropolymerisation conditions for these polymers have been investigated and optimised to produce the best photovoltaic device. In addition, the use of different liquid electrolytes, such as ionic liquids, has been examined in this work. As compared to the devices described by other research groups, significant improvement of photovoltaic responses for open circuit voltage (Voc) and short circuit current (Isc) has been observed using these new types of solar cells. The porphyrin group in the conducting polymers has been shown to play a significant role in the improved energy conversion (from sunlight to electricity) for photovoltaic devices.

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