Tiny crystal flower blooms in a furnace

(Image: Chun Li, Liang Huang, Gayatri Pongur Snigdha and Linyou Cao, North Carolina State University)

 A rose by any other name might smell as sweet, but it's unlikely to be this small. This beautifully intricate flower-like structure has petals only 20 to 30 nanometres thick - making the world's smallest orchid look like a triffid. Linyou Cao at North Carolina State University in Raleigh and colleagues made it out of germanium sulphide dust. They weren't interested in nanohorticulture so much as finding a way to boost the capacity of the next generation of energy storage devices, such as lithium-ion batteries and supercapacitors. Germanium sulphide is a semiconductor material, and the tiny crystalline bloom's promise is due to its relatively enormous surface area packed into a tiny space. The material is also good at absorbing sunlight and converting it into usable power, making this little flower a potential solar cell. The team synthesised it by vaporising germanium sulphide powder in a furnace and then cooling the vapour in a controlled way so that it settled in thin petal-like layers that branched out from one another. They also found that the nanosheets grew at a speedy 3 to 5 micrometres a minute, an order of magnitude faster than comparable nanosheets or nanowires.