Upconversion allows silicon solar cells to make use of infrared light.
- An invisible infrared laser beam, coming from the left, is incident on two upconverter samples. In the upconverter samples the laser ray is visible to the naked eye due to upconversion.
"Every semiconductor material has an inherent upper efficiency limit for the conversion of sunlight into electrical energy. By employing so-called upconverters, these limits can be overcome and higher solar cell efficiencies can be achieved. In silicon solar cells, upconverters modify the infrared part of the solar spectrum so that the solar cell is able to use that part. (…) The upconverters help to increase the electrical yield. The theoretical limiting efficiency of silicon is about 30 percent. With upconversion, this limit can be increased to 40 percent."