A report out of Stanford University gives hope for significant improvement in efficiency of solar collectors. Co-team leader Shanhui Fan, a professor of electrical engineering, said of the research “Nanocrystalline-silicon is a great photovoltaic material. It has a high electrical efficiency and is durable in the harsh sun. Both have been challenges for other types of thin solar films.”
Nanocrystalline-silicon’s major drawback, however, has been its relative poor absorption of light, making them inefficient.
The Stanford team developed what they call nanoshells from tiny balls of silica coated with silicon. They then remove thee glass center with acid that does not affect the silicon, leaving behind the light-sensitive shell. These shells form optical “whispering galleries” (similar to those that trap sound in buildings such as the US capitol) that capture and recirculate the light.
“The light gets trapped inside the nanoshells,” said Yi Cui, associate professor of materials science engineering at Stanford. “It circulates round and round rather than passing through and this is very desirable for solar applications.”
This is purely research at this time, and will take years to make commercially viable product, but a promising advance in solar technology.