New material could provide massive boost to solar cell efficiency
- By Joel Hruska on June 23, 2014 at 3:25 pm
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Traditionally, solar cell technology has struggled to overcome a significant efficiency problem. The type of substrate used dictates how much energy can be absorbed from sunlight — but each type of substrate (silicon, gallium arsenide, indium gallium arsenide, and many others) corresponds to capturing a particular wavelength of energy. Cheap solar cells built on inexpensive silicon have a maximum theoretical efficiency of 34% and a practical (real-world) efficiency of around 22%. Multijunction cells that use multiple substrates to capture a larger section of the sun’s spectrum can reach up to 87% efficiency in theory, but are currently limited to 43% in practice. What’s more, these types of multijunction cells are extremely expensive — wiring and laying out precise structures is far more difficult than a simple thin film silicon cell.
We have a vast array of cells, but all of the inexpensive, common designs are low-efficiency. Image courtesy of Wikipedia
The polychromat layer sits on top and splits energy wavelengths, aiming them at the layers where they’ll be absorbed.
Given that the biggest barrier to III-V multi-junction solar cell technology is manufacturing complexity and associated cost, anything that boosts cell efficiency on the front end without requiring any major changes to the manufacturing process is going to help with the long-term commercialization of the technology. Until now, most of the multijunction devices deployed go into space or are used by for military applications where cost is less of an issue and peak performance is essential. Advances like this could help make technologies cost effective for personal deployment and allow them to scale in a similar fashion to cheaper devices.
http://www.extremetech.com/extreme/184977-new-material-could-provide-massive-boost-to-solar-cell-efficiency