The sun is a bountiful source of energy for our planet. .With the advent of photovoltaic cells, man has begun harnessing the sun's radiant energy, turning it into a form more directly useful: electricity. Commercially available solar cells currently operate at about 13% efficiency, sufficiently high to make them a viable source of electrical energy. It is of great interest, however, to improve their conversion efficiency, and to lower the cost of production so as to make them more economical, and thereby reduce our dependence upon traditional "dirty" sources of energy such as coal and oil. It has been found that an electrode coated with a thin film of nanocrystalline titanium dioxide, a very inexpensive and commonly available semiconductor, can be sensitized with a strong light-absorbing dye which can absorb the energy of sunlight and then transfer this energy as electronic charge into the electrode. A cell containing such an electrode is capable of producing a photocurrent at an appreciable voltage. The search is on to find the best sensitizing dye. It must absorb as much of the incident sunlight as possible, be capable of strong adsorption onto Ti02 so as to promote electron injection into the semiconductor, be relatively cheap and easy to synthesize, and be photochemically stable. It was the intent of this research to synthesize and test such a dye, a porphyrin dyad. The dyad was to be made from an electron donating moiety, meso-tetrakis(4-aminophenyl)porphyrin (TAPP), linked by an amide bond to an electron acceptor, meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP). This material eluded attempts at synthesis, due to the poor reactivity of the aminoporphyrin and to the difficulty in ensuring that only one amide bond formed. Characterization of the monomers was carried out, and conditions for their chromatographic separation were determined. Recommendations for successful synthesis of the dyad are given.
| Identifer | oai:union.ndltd.org:pdx.edu/oai:pdxscholar.library.pdx.edu:open_access_etds-6048 |
| Date | 13 June 1995 |
| Creators | Braden, Dale A. |
| Publisher | PDXScholar |
| Source Sets | Portland State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Dissertations and Theses |
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