triple-junction solar cell efficiency record

Sharp has a long string of solar cell efficiency records. And it has just extended that string a little further.

In 2009, Sharp landed a 35.8% triple-junction, non-concentrator solar cell efficiency record. It then went on to break that record a couple more times — with others breaking it as well. Up until recently, that record sat at 37.8%, and Boeing-Spectrolab was the record holder. But Sharp now reports that it has increased its cell efficiency from 37.7% (the record before Boeing-Spectrolab came along) to 37.9%. The efficiency record has been verified by National Institute of Advanced Industrial Science and Technology (AIST).

So, Sharp is in the lead again.

If you don’t follow such technology closely, let me quickly explain what a couple of these key terms mean. Conventional solar cells are “single-junction” solar cells, so they are just tuned to one wavelength of light. That greatly limits the efficiency of the solar cells. “Multi-junction” solar cells (in this case, triple-junction solar cells) add junctions using different materials in order to capture more wavelengths of light.

Of course, this has drawbacks — it’s more expensive and more difficult, for example — but it can considerably increase solar cell efficiency. As you can see in this NREL graph on solar cell efficiencies, multi-junction solar cells rule the roost when it comes to efficiency (note: the graph doesn’t yet include Sharp’s new record):

Click to enlarge this beast.