China collaboration leads to new solar cell research
Research arising from a summer visit by two PhD students from China could lead to cheaper, greener, more flexible solar cells.
The research, which was led by Dr Imalka Jayawardena, a researcher in the Advanced Technology Institute (ATI) was published in ‘Nanoscale’, a leading Royal Society of Chemistry publication, in July 2015.
Dr Jayawardena oversaw the two PhD students, Siying Li and Sujie Chen from Shanghai Jiao Tong University during their eight week stay, which was spent conducting research in the ATI’s cleanroom. Sponsored by Santander and organised at Surrey by Dr Radu Sporea, the exchange scheme has seen three visits by students from China over the past two years.
One of the students’ aims during their visit to Surrey was to explore the application of zinc oxide, a semiconductor material developed for transistors, sensors and other electric elements, into solar cells. While industrial solar cells use silicon for this purpose, the type of zinc oxide the students used came in the form of an ink which can be applied to a large number of flexible materials using conventional printing methods. This means the technology could lead to applications such as portable chargers, wearable devices and transparent windows.
Unlike most zinc oxide inks, which contain a toxic component, the ink used by the students from China is water-based, making it safer for industrial scale printed electronic fabrication processes. This latest research built on previous work and drew on the University of Surrey’s expertise in fabricating high efficiency, large area solar cells to match the zinc oxide ink with carbon based solar cell materials. It proved that not only are these solar cells efficient, they can also offer long life (at least 200 hours), even in the absence of an additional protective barrier layer to prevent moisture and oxygen from getting into the device and degrading it. It was also found that the zinc oxide-based cells needed no light pre-treatment which is normally necessary for the type of solar cells used in this work.
Dr Jayawardena commented, “We were pleased to welcome Siying Li and Sujie Chen to the ATI and delighted that they were able to achieve so much in such a short space of time. It is not often that an 8-week placement leads to such high quality work that can impact a field such as organic electronics”.
“The research offers an environmentally-friendly, safe and inexpensive way of producing solar cells which could have broad use as we enter the era of the Internet of Things. Building on this research, we will be looking at incorporating the technology into a newer type of hybrid solar cell which is showing strong promise as a low cost, but equally efficient competitor for silicon-based solar cells.”
Read the research paper, ‘High efficiency air stable organic photovoltaics with an aqueous inorganic contact’.