Question: why did you want to study solar cells process mimic photosynthesis.

Laura Tobin answered on 10 Nov 2014:

Hi Lauren,

I have always been interested in renewable energy. I wanted to study optics and I felt it was a huge and diverse area, that if I didn’t like one part I could move to a different area. Optics covers everything from data storage, astrophyiscs, medical imaging and renewable energy. When I was offered a chance to study these solar cells, I jumped at the chance as it covered two areas I was interested in – solar/renewable energy and optics.

Traditional solar cells are made out of silicon and are semiconductor devices. This means that have an efficiency limit (Shockley–Queisser limit) of about 33.7%. This means that we can theoretically only convert just over a third of the light hitting the solar cells into electricity. Also there are a lot of other problems, such as you need direct sunlight and the refined silicon is expensive to produce.

My solar cells are different and that limit doesn’t apply to them. The are photoelectrochemical devices. There is a chemical reaction instead of the electric semiconductor one. This chemical process is similar to photosynthesis – sunlight (PHOTO) hits the solar cell/ leaves and this starts the CHEMICAL reaction to produce an electric current. These cells are cool because they use a dye (like plants use chlorophyll), so that means the solar cells can come in many different colours. The downside is the best dyes to produce the most current and a horrible colour. These solar cells have another advantage, they work in diffuse sunlight i.e. they do not need direct sunlight so they can work in Ireland (as the clouds give us a lot of diffuse light) and the work indoors too. At the moment though the highest efficiencies are only around 14% as the research is quite new (when compared to silicon solar cells).