Researchers create LED lights from rice husks

Researchers at the Hiroshima University have developed a method to create silicon quantum dot (QD) LED lights from recycled rice husks.

The method could overhaul agricultural food waste by turning the waste product into LED in an environmentally friendly way.

Traditional silicon quantum dot production requires toxic materials such as cadmium, lead or other heavy materials. Risks husks contain a reliable source of high-purity silica and Si powder, which enabled the development of the quantum dots.

The researchers milled rice husks, heating the resulting silica powder in an electric furnace to obtain Si powders via a reduction reaction.

The now purified Si powder was reduced to just three nanometres in size via chemical stability and high dispersivity in solvent, with three nm crystalline particles to produce QD LED lights that luminesce in the orange-red range with luminescence of over 20%.

The LEDs were assembled were assembled as a series of material layers, using an indium-tin-oxide glass substrate as an LED anode. Additional layers were spin-coated onto the ITO glass before the material was capped with an aluminium film cathode.

Ken-ichi Saitow, lead study author and professor of chemistry, Hiroshima University, explained: “This is the first research to develop an LED from waste rice husks. 

“By synthesising high-yield SiQDs from rice husks and dispersing them in organic solvents, it is possible that one day these processes could be implemented on a large scale, like other high-yield chemical processes

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