Researchers at Purdue University are developing a solar cell designed with the ability to self-heal in order to improve service life.
According to assistant professor of mechanical engineering Jong Hyun Choi, the research centres around even closer mimicking of natural photosynthetic systems in plants by using carbon nanotubes and DNA.
Synthetic photosynthesis processes in relation to solar cells faces a major challenge – serviceable life. While silicon based solar cells, such as those used in a “mainstream” solar panel have a life of 25 years or more, dye sensitised (photoelectrochemical) solar cells currently have a maximum life of a decade.
Photoelectrochemical cells utilize an electrolyte to carry electrons and create the current. The cells contain light-absorbing dyes called chromophores, molecules that perform the same function as chlorophyll in plants. However, these chromophores degrade over time due to exposure to sunlight. Plants address this by continually replacing chlorophyll.
Like plants, the new technology has the potential to create a photoelectrochemical solar cell that replaces its damaged chromophores and could continue to function at full capacity indefinitely.
In the system, carbon nanotubes act as molecular nanowires and as anchor points for strands of DNA. When the chrompophores are ready to be replaced, the DNA is introduced. It recognizes and attaches to the chromophores, dissolves them and then the system spontaneously self-assembles.
Professor Choi says using natural chromophores in such a system would be costly and difficult on an industrial scale as they need to be harvested and isolated from bacteria, so the team is looking at making synthetic chromophores made of dyes called porphyrins.
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