An “exotic” material belonging to a class of materials called “topological insulators” could help solar cells and optical communication devices evolve. A team of scientists from Stanford and SLAC have noticed that ultra-thin sheets of that material remain transparent and highly conductive even in the harshest conditions.
To be more precise, the researchers flexed, folded and creased the sheets for 1,000 times. “It’s rare for a good conductor to be both transparent and durable as well,” said Zhi-Xun Shen of SLAC and Stanford’s Institute for Materials and Energy Sciences (SIMES).
The material is made of 1-atom-thick sheets (resembling graphene) of bismuth and selenium, having the shape of a five-layer sandwich. The resulted material was characterized through a lack of bonding of its different sheets, so in its entirety the sheet is very flexible.
Topological insulators are materials that conduct electricity on on their surface, while their insides remain insulating. The bismuth selenide layer is responsible for the conduction part in the new material. However, unlike other materials (among which gold would be the nearest equivalent in terms of conductivity), bismuth is transparent to infrared light, and hence its usability in solar cells, a feature few technologies can do nowadays.
Bismuth selenide also doesn’t get significantly affected by the humidity or oxidization to which they’re exposed during the manufacturing process.
Solar cells are currently passing a crisis of efficiency innovations. Prices have gone down lately and one can intuitively say it’s now time for more innovations like this to make a difference in this industry. Along with solar cells, heat-scavenging devices will also benefit from this kind of material a lot. They’re particularly useful in cars and power plants (be them coal- or nuclear-powered), where from this standpoint efficiency is lacking big time.