by Sanjeev Kulkarni
Econintersect: The quest for improving solar panel conversion efficiency has gotten another boost. Engineers at Stanford University have fabricated nanoshell whispering galleries. These galleries not only hold promise for further improvement in solar conversion efficiency but also reduction of manufacturing costs of solar panels and the development of a number of unique new solar energy product areas.
According to the Stanford University website:
These photovoltaic nanoshells that harness a peculiar physical phenomenon to better trap light in the solar materials. The results could dramatically improve the efficiency of thin-film solar cells while reducing their weight and cost..
The engineers call their spheres nanoshells. Producing the shells takes a bit of engineering magic. The researchers first create tiny balls of silica — the same stuff glass is made of —and coat them with a layer of silicon. They then etch away the glass center using hydrofluoric acid that does not affect the silicon, leaving behind the all-important light-sensitive shell. These shells form optical whispering galleries that capture and recirculate the light.
The researchers estimate that light circulates around the circumference of the shells a few times during which energy from the light gets absorbed gradually by the silicon. The longer they can keep the light in the material, the better the absorption will be.
This “clever structure” has several advantages. It can be fabricated more cheaply using less material. And cost is just for starters – other uses are envisaged. Since the nanoshells are less sensitive to the angle of incoming light they might open up new applications such as solar sails on the high seas or photovoltaic clothing for mountain climbing and other wilderness activities.
The following scanning electron microscope image from Stanford shows a mono-layer cross-section of the new structure:
This research was carried out at the Center for Nanostructuring for Efficient Energy Conversion (CNEEC) at Stanford University, with awards from the U.S. Department of Energy.
Econintersect has been tracking the solar energy story. Investors have found it difficult to make money from solar energy. But who knows? ‘Careless Whispers’ on this optical whispering gallery might ruin a good investment opportunity!
Sources and References:
- New Semiconductor Technique May Lead to Dramatic Changes: Econintersect