- Category: Solar
02 Oct 2012
- Published on Tuesday, 02 October 2012 09:24
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It won’t be too long before buildings have the ability to generate their own electricity from roofs, walls, windows and even benchtops that work similarly to solar panels.
A consortium of Australian research institutions and industry partners is working to develop solar cell technology that can harness energy from the sun through walls, windows and steel roof sheeting, significantly improving the overall energy efficiency of buildings.
Dubbed as the Victorian Organic Solar Cell Consortium, the collaboration is backed by A$3.4 million (U.S. $3.5 million) grant from the Victorian and Commonwealth governments awarded late last year. The consortium includes the Monash University, the University of Melbourne, Australia’s national science agency the Commonwealth Scientific and Industrial Research Organization, and industry partners BlueScope Steel, Securency International, Bosch and Innovia Films.
Using “dye-sensitized solar cells” and “heterojunction solar cells” that can be printed on flexible materials, the project aims to come up with a commercial process that could be a viable alternative to traditional silicon solar photovoltaic cells.
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Dye-sensitized and heterojunction solar cells
When struck by sunlight, the dye-sensitized solar cells create electrons that are carried out by semiconducting titanium oxide through an external circuit, generating power. The circuit then sends the spent electrons back to the solar cell, where they react with an electrolyte and restore the dye cells, preparing them to generate another electron.
“Silicon-based cells work well when the sun is high but shut down when the light falls below certain levels. Meanwhile, dye-sensitised cells harvest light from any direction so they can work in diffuse light. They will produce energy from lower levels of light than silicon cells,” described Leone Spiccia, Professor of Chemistry at the Monash University.
In addition, Professor Yi-Bing Cheng, a materials engineering specialist at the University, said the dye-sensitised solar cells can also come in different colors, even transparent.
“The possibility of a color range and capacity to work from diffuse and weak light sources make dye-sensitised cells particularly exciting. It means cells can be integrated into a range of surfaces, including walls, benchtops and windows, both inside and outside buildings, to boost their energy efficiency,” he stressed.
Moreover, "the possibility of using the cells to create different patterns and shapes [inside the buildings] is very appealing," added Professor Cheng.
As for the heterojunction solar cells, light produces electron–hole pairs called excitons, with subsequent separation of charges in the boundary between an electron donor and acceptor. These charges then transport to the device’s electrodes where these charges flow outside the cell, generate electricity and then re-enter the device on the opposite side.
“Both technologies can be printed, however the translation of each technology to large scale has its own unique development problems, which are being examined. To reduce the cost of solar cells, we need to improve the efficiency, improve durability and translate device assembly to high volume production processes,” said the University of Melbourne.
To date, the collaboration has delivered improvements in the materials used in the process. Consequently, they are seeking to advance the printing procedure of the cells to industrial levels.
Generally, there aren’t too many projects with the scale of concerted effort such as the Victorian Organic Solar Cell Consortium, said Professor Cheng. Overall, global effort remains small to push this technology at a large scale, he added. – C. Dominguez