Carbon Nanoflorets

• Carbon nanoflorets made by IIT Bombay researchers can convert incident sunlight to heat with 87% efficiency.

ABOUT CARBON NANOFLORETS

• These are like tiny marigold flowers made only of carbon, which are called as the material carbon nanoflorets.
• Researchers heated a special form of silicon dust called DFNS (for dendritic fibrous nanosilica) in a furnace. Once heated, acetylene gas was introduced into the chamber.
• The white powder turned black – a sign that carbon had been deposited on the DFNS.
• The black powder was collected and treated it with a strong chemical that dissolved the DFNS away, leaving carbon particles behind.
• The structure of the silicon particles – 50-1,200 nanometers in size—resembled spikes arranged around a sphere.
• The carbon nanoflorets’ high efficiency comes from three properties
  • The nanoflorets absorb three frequencies in sunlight – infrared, visible light, and ultraviolet whereas other common materials like photovoltaic materials used in solar panels, absorb only visible and ultraviolet light.
    • More than half of the energy in sunlight arrives to the earth as infrared radiation.
    • So the nanoflorets can absorb much more energy from the sun.
  • The other two properties responsible for the material’s high light-heat conversion efficiency are a result of its shape.
    • As light falls on the material, the carbon cones ensure that very little is reflected back. Instead, most light is reflected internally.
    • The carbon nanoflorets don’t lose heat to its environment, however, thanks to long-range disorder- parts of the structure at some distance from each other possess different physical properties.
    • As a result, heat waves in the material aren’t carried over long distances, reducing the amount of heat dissipated away.