A team of chemists at the University of California Riverside (UCR) has found a way to boost solar photovoltaic efficiencies by 30 percent or more. By combining inorganic semiconductor nanocrystals with organic molecules, they have succeeded in “upconverting” photons in the visible and near-infrared regions of the solar spectrum.
The infrared region of the solar spectrum passes right through the photovoltaic materials that make up today’s solar cells. That energy is lost regardless of the quality of the solar cell. The hybrid material — cadmium selenide nanocrystals coated with organic ligands — captures two infrared photons that would normally pass through a solar cell without being converted to electricity. The inorganic component absorbs the two photons and passes their energy on to the organic component for combination. The organic compounds then produce one high-energy photon, which is readily absorbed by photovoltaic cells, generating electricity from light that normally would be wasted.
Essentially, these materials are reshaping the solar spectrum so that it better matches the photovoltaic materials used today in solar cells, the researchers say.
Besides solar energy, the ability to upconvert two low-energy photons into one high-energy photon has potential applications in organic light-emitting diodes.
The UCR Office of Technology Commercialization has filed a provisional patent on the technology.
Researchers at the University of Texas at Arlington have also found a way to improve solar technology. They have developed an energy cell that can store large-scale solar energy even when it’s dark.