Better Optimizing Thin Film Solar Cells for Lower Cost
For many people, the thought of solar power brings to mind arrays of silicon panels or massive reflectors, aiming light to a point. These are not the only examples of solar power technology though, and one of them may be seeing a drop in cost soon. Researchers at the University of North Carolina recently found a way to optimize the design of thin film solar cells that could reduce the amount of amorphous silicon used by an order of magnitude.
The best thin film solar cells today use a layer of amorphous silicon roughly 100 nm thick, and it captures most of the solar energy that falls on it. What the researchers design uses a 10 nm thick layer and absorbs 90% of available solar energy. This was achieved by examining the absorption of semiconductor materials in light-trapping techniques, like those of a thin film solar cell. The researchers found that absorption is maximized when the light-trapping efficiency and absorption efficiency match. From this they designed a layered, rectangular design which could potentially be used to improve the performance of thin film solar cells based on materials other than silicon.
One of the challenges to manufacturing and cutting the cost of thin film solar cells is the deposition of the semiconductor material. By reducing the amount needed by an order of magnitude, the cells could be produced faster and more cheaply.
Source: North Carolina State University