In other research, scientists have developed a solar cell capable of collecting multiple electrons for each high-energy photon absorbed. They have also found a way to directly measure the electron output. Conventional solar cells convert one wavelength of light efficiently, and either fail to absorb other wavelengths of light or throw away extra energy as heat. The researchers have shown that it is possible to capture some of the extra energy by transferring the energy in each high-energy photon to more than one electron. The approach could be used to product ultra-efficient yet inexpensive solar cells.
The material involved in this research, quantum-dot test cells, is so thin that almost all light passes through it unabsorbed. The next step in this development is to add a thin layer of this material to an extremely porous material with a large surface area. Scientists are also working with different types of quantum dots that have potential to absorb and convert more light.