As the reserves of the traditional sources of energy shrink, the development of renewable sources has become a more important line of research. The new forms of silicon-based energy production are not as cost-effective as they could be. A group of researchers led by Yabing Qi is studying solar cells made of organic materials, with flexible and transparent electrodes, which will make it possible to manufacture solar cells cheaply.
In a recent paper published in the journal Organic Electronics, Qi and his research group characterise electrodes made of new materials, among them a plastic, a conducting material and zinc oxide. They have also successfully established the methods by which the electrodes should be cleaned to restore their conductivity and their performance after a long period of storage, and so have helped to optimise the production of these new solar cells.
Traditional silicon-based solar cells are expensive to produce because of the cost of the raw material and the strict manufacturing requirements. Silicon solar cells are also rigid and opaque, which limits how they can be used and where they can be placed. Qi and his colleagues work with flexible current-conducting materials that are transparent as well. Making "Flextrodes" (the name given to these flexible transparent electrodes) is more cost-effective. They are easier to produce because they are flexible. The main component of a Flextrode is polyethylene terephthalate, a cheap and readily available plastic found in disposable drinks bottles. The ways they can be used and placed are more varied than for silicon cells. They can even be fitted to windows, since organic solar cells can be made partly transparent.
Qi and his colleagues were able to show that two common cleaning methods, one using ozonation and UV treatment and the other plasma treatment, were effective in removing contamination and restoring the function of the Flextrodes. The study showed that these methods can easily be built into the manufacture of solar cells to regenerate Flextrodes.
Qi is enthusiastic about the future of these inexpensive organic solar cells. His laboratory is working on the design and the optimisation of new cells. The technology may soon be available for wide public use.