UBC Theses and Dissertations
Enhancing the photovoltaic performance of biogenic solar cells with synthetic biology Einarsson, Sean
The development of organic photosensitive materials has opened up a breadth of new areas for advancement in photovoltaics and dye-sensitized solar cells (DSSCs). The approach of organic DSSCs is to use photo-excitable dyes over a conductive nanoparticle layer in the presence of an electrolyte to create a working electrode. There has been a large emphasis on the improvement of organic DSSCs in recent years, and there have been significant increases in their photovoltaic efficiencies. However, the fabrication process and extraction of the dyes involves complicated and costly methods that require the use of toxic chemicals and a tightly controlled clean-room environment. To alleviate these issues, a novel approach was developed that uses genetically engineered bacteria capable of producing lycopene, a photo-excitable dye, internally. Preliminary research of these genetically engineered cells implemented in organic solar cell production shows promising results, but significant improvements must be made in order to be comparable to conventional solar cells. The thesis focuses on improving the conductivity of the genetically engineered bacteria capable of synthesizing lycopene. The approach is to use the electroconductive properties found in another bacterial species, Shewanella Oneidensis MR-1 (SO MR-1), to increase the photovoltaic properties of the system. The conductive ability of SO MR-1 arises from its bacterial nanowires which are capable of extracellular electron transfer. The experimental methods include identifying the genes that are responsible for bacterial nanowires formation in SO MR-1, extracting and cloning the identified genes into the lycopene producing bacteria, verifying the expression of the bacterial nanowire genes, evaluating the photovoltaic characteristics, and comparing the measurements of the systems with and without bacterial nanowires. The results show successful implementation of the genes responsible for bacterial nanowire formation into the lycopene producing bacteria, but the expression level analysis revealed ambiguous results which could be addressed with more precise methods. The photovoltaic analysis had some issues with short-circuiting, which made it difficult to draw any significant conclusions. Although the main objective of the thesis might need to be further investigated, several integral objectives were achieved, which can be used as a stepping stone in future research.
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