This flower-like structure is made out of germanium sulfide (GeS), a semiconductor material that has extremely thin petals with an enormous surface area. The GeS flower may help boost the energy performance for the next generation for storage devices and solar cells.
The scientists published their findings in the journal ACS Nano. The GeS nanoflower has petals that are only 20 to 30 nanometers thick, providing a large surface in a small amount of space. This could significantly improve the capacity of lithium-ion batteries, since this thinner structure could hold more lithium ions. They could also lead to increased capacity for supercapacitors, which are used in energy storage.
In order to create this flower-like structure, the researchers heated up GeS powder in a furnace until it began to vaporize. This vapor is then blown onto a cooler region of the furnace, where the GeS settles into a layered sheet that is 20 to 30 nanometers thick and roughly 100 micrometers long. Once additional layers are added, the sheets branch out from one another, creating a floral pattern reminiscent of marigolds or carnations.
It’s important to control the flow of the GeS vapor so that it spreads out in layers rather than aggregating into clumps, states Linyou Cao, material scientists at NC State. GeS is similar to graphite, which can settle into neat layers or sheets. However, its atomic structure makes it very good at absorbing solar energy, and converting it into useable energy. GeS is inexpensive and non-toxic, making it an attractive option for solar cells.
Reference: “Role of Boundary Layer Diffusion in Vapor Deposition Growth of Chalcogenide Nanosheets: The Case of GeS” by Chun Li, Liang Huang, Gayatri Pongur Snigdha, Yifei Yu and Linyou Cao,25 September 2012, ACS Nano.