Increasing Photocurrents in Biosolar Cells using Microporous Electrodes - A Feasibility Study

Solar energy (or photovoltaic energy) offers a technology for large scale energy generation which avoids the pitfalls of existing fossil fuel methods where coal, oil or gas which, when burnt, generate huge amounts of carbon dioxide which causes climate change along with other undesirable waste products (e.g. sulfur dioxide which causes acid rain). Solar energy can be captured in a number of ways (e.g. using crystalline or amorphous silicon or gallium arsenide solar cells). These solar cells can be fabricated to be very efficient (for instance for use in space applications). However, their major drawback is that they are expensive both in monetary terms and in terms of the energy used to produce them. This leads to longer pay-back times for this type of technology.Nature has developed its own form of solar cells in the form of photosynthesis which is sufficiently effective to support the entire plant-based biosphere of the planet. Photosynthesis operates by light being absorbed to create an electrical potential difference when water is split into oxygen, protons and electrons. This takes place in the chloroplast of cells which are held in plant leaves. Within these chloroplasts, lie thylakoid membranes and these membranes are where photosynthesis takes place.In this proposal, we will test the feasibility of extracting photosynthetic thylakoid membranes, attaching them to optimized gold-coated electrodes and using the resulting solar cells as low cost solar energy harvesters. It is known that such solar cells are capable of generating very small photocurrents. Thus, the principal aim of this proposal is to increase these photocurrents (by optimizing electrode design and thylakoid production) so that the technology can become a viable commercial technology.