Rice milling is separated from the rice husks and produces about 100 million tons of rice husk waste globally each year. Scientists in Japan have used recycled rice husks to create the first silicon quantum dot LED lamp, which converts agricultural waste into state-of-the-art light-emitting diodes in a low-cost, environmentally friendly way. The findings were recently published in the American Chemical Society journal ACS Sustainable Chemistry and Engineering.
"Since typical quantum dots usually involve toxic substances such as cadmium, lead, or other heavy metals, environmental concerns arise when using nanomaterials," said the study's lead author, Kenichi Saito, a professor of chemistry at the Natural Science Basic Research and Development Center at Hiroshima University in Japan. are often considered. Our proposed quantum dot process and fabrication method minimizes these concerns."
The research team used a combination of milling, heat treatment and chemical etching to process the rice husk silica: first, they milled the rice husk and extracted the silica powder by burning the organic compounds in the milled rice husk; second , they heated the generated silicon dioxide powder in an electric furnace, and obtained silicon powder through reduction reaction; thirdly, purified silicon powder of 3 nanometers was further obtained by chemical etching; finally, the surface was chemically functionalized to make it have With high chemical stability and dispersibility in solvents, silicon quantum dots with luminescence in the orange-red range were prepared with 3-nanometer nanocrystalline particles, and the luminous efficiency exceeded 20%.
The chemical synthesis method developed by the research team allowed them to evaluate the optical and optoelectronic properties of silicon quantum dot LEDs, including the structure, synthesis yield, and performance of silicon dioxide, silicon powder, and silicon quantum dots. Next steps for the team include developing higher luminous efficiencies in silicon quantum dots and LEDs. They will also explore the possibility of producing silicon quantum dot LEDs other than red-orange.
