An international team of researchers from the University of Oxford, National University of Singapore, and the University of Boston have developed an atom-thin photovoltaic device with high quantum efficiency.
With a quantum efficiency of 30%, or, translated into layman’s terms, the number of photons converted into charge-carrying electrons, the researchers hope the end result will lead to overall boosted solar system performance.
The researchers created a sandwich of a semiconducting transition metal dichalcogenide (TMDC) and sheets of graphene, creating a new range of heterostructures. Heterostructures are semiconductor materials where size restricts the movements of the charge carriers forcing them into a quantum confinement. These heterostructures are based on two-dimensional atomic crystals. The size of these heterostructures might lead to the creation of flexible solar cells or phototransistors.
TMDCs are very powerful and have strong photon-electron interactions due to its layered materials that form a kind of lattice. This innate design makes electrons very sensitive to light stimulation.
Researchers are excited by TMDCs and see them as potentially excellent transistors, since the off current is very low and the on current mostly likely will be high. TMDCs ability to interact with light makes them very sensitive photodetectors.
The next step for researchers will be to investigate two dimensional semiconductor crystals to determine whether or not an increase in efficiency is possible. Other experiments with different materials will be performed in order to create novel heterostructures, giving researchers clues in how to boost overall solar system performance.