Scientists have designed and constructed a prototype for a new solar cell that integrates multiple cells stacked into a single device capable of capturing nearly all of the energy in the solar spectrum.
A George Washington University researcher helped design and construct a prototype for a new solar cell that integrates multiple cells stacked into a single device capable of capturing nearly all of the energy in the solar spectrum.
Scientists have worked to develop more efficient solar cells for years, however this approach has two novel aspects. It uses a family of materials based on gallium antimonide (GaSb) substrates, which are usually found in applications for infrared lasers and photodetectors. These GaSb-based solar cells are assembled into a stacked structure along with high efficiency solar cells grown on conventional substrates that capture shorter wavelength solar photons. In addition, the stacking procedure uses a technique known as transfer-printing, which enables three dimensional assembly of these tiny devices with a high degree of precision.
This particular solar cell is very expensive, but researchers believe it was important to show the upper limit of what is possible in terms of efficiency. Despite the current costs of the materials involved, the technique used to create the cells shows promise, researchers say. Eventually a similar product enabled by cost reductions from very high solar concentration levels and technology to recycle the expensive growth substrates could be brought to market.
The research builds off of the advancements made by the MOSAIC Program, a $24 million research project funded by the Advanced Research Projects Agency-Energy that funds 11 separate teams across the United States seeking to develop technologies and concepts to revolutionize photovoltaic performance and reduce costs. Funding for this type of research is essential for developing viable commercial technology in the future, the researchers said.
The new design, which converts direct sunlight to electricity with 44.5 percent efficiency, has the potential to become the most efficient solar cell in the world.