Austrian researchers have created a diode from a single atom layer of tungsten diselenide, possible opening ways for future ultra-thin photovoltaics.
Despite being overshadowed by the acclaimed ‘wonder material’ graphene, tungsten diselenide might, researchers believe, offer even better performance in some areas while maintaining the advantages of a single-atom layer.
Tungsten diselenide consists of one layer of tungsten atoms surrounded by selenium atoms above and below the tungsten plane. The material absorbs light and, unlike graphene, allows its direct conversion into electric power.
The experiment conducted at the Vienna University of Technology has been described in an article published in the latest issue of the Nature Nanotechnology journal. Two other teams, from the University of Washington and the Massachusetts Institute of Technology, have also conducted experiments with tungsten diselenide, coming to similar conclusions. The three studies are underlining the promising potential of tungsten diselenide in the field of flexible electronics and ultra-thin photovoltaics as an alternative to graphene.
“The electronic states in graphene are not very practical for creating photovoltaics”, said Thomas Mueller, the lead researcher behind the study, explaining why his team turned away from graphene,
A single layer of tungsten diselenide is so thin that 95 per cent of the light just passes through. However, a tenth of the remaining 5 per cent absorbed by the material is converted into electrical power. To increase the efficiency, panels could be designed with a multi-layered structure, with each additional layer increasing the amount of light turned into electricity.
However, the team believes the high transparency could also offer benefits. “We are envisioning solar cell layers on glass facades, which let part of the light into the building while at the same time creating electricity,” Mueller said.