- Category: Technology
29 Aug 2012
- Published on Wednesday, 29 August 2012 11:15
- Hits (1238)
A new solar material developed by RTI International can be produced for less than $20 per square meter, reducing the cost of solar energy and speeding up its market adoption, the company said.
RTI solar cells are formed using solutions of semiconductor particles known as colloidal quantum dots. They were created using cheaper materials and processing technologies, which allow it to be produced 75 percent cheaper than traditional solar cells.
Though the demonstration tests give the cells relatively low power conversion efficiency – 5 percent compared with the lower end average 15 percent for commercial crystalline silicon cells – it is comparable with other emerging PV materials such as thin-film.
The researchers are confident that with some tweaking they can increase the efficiency of their solar cells.
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According to Jay Lewis, a senior research scientist at RTI, the efficiency of a solar device is primarily limited by the amount of sunlight it can absorb.
“There are many well-known techniques to enhance absorption, which suggests that the performance can increase substantially,” said Mr. Lewis.
One way could be in tweaking the material itself as quantum dots have been proven to have tunable optical and electronic properties.
Colloidal quantum dots are inorganic semiconductors that are only a few nanometers in size, so the RTI cell already manages to get good results while using less material compared with a traditional solar cell.
Conventional semiconductor material used in PV usually can only harvest visible light, but this is only a portion of the available light from the sun. Quantum dots have been observed to have a greater sensitivity to different frequencies of the solar spectrum. The wavelengths of lights they can absorb depends on factors such as what the quantum dots are made of or their size and shape.
In the case of the RTI cells, they have a high sensitivity to infrared light, which allows them to utilize more of the available solar spectrum for power generation.
Composed of lightweight, flexible layers, the cells have the potential to be manufactured using high volume roll-to-roll processing and inexpensive coating process. They can also be processed at room temperature, further reducing input energy requirements and costs.
According to the researchers, the technology addresses many of the major cost drivers of P.V., paving the way for solar projects with a lower up-front cost. The upfront cost of P.V. installations can be a barrier to its acceptance as solar energy is usually priced at a higher rate than power from fossil-fuel plants as developers need to make up for their initial investment. – K.R. Jalbuena