World's first LED lights developed from rice husks:
Milling rice to separate the grain from the husks produces about 100 million tons of rice husk waste globally each year. Scientists searching for a scalable method to fabricate quantum dots have developed a way to recycle rice husks to create the first silicon quantum dot (QD) LED light. Their new method transforms agricultural waste into state-of-the-art light-emitting diodes in a low-cost, environmentally friendly way.
[...] "Since typical QDs often involve toxic material, such as cadmium, lead, or other heavy metals, environmental concerns have been frequently deliberated when using nanomaterials. Our proposed process and fabrication method for QDs minimizes these concerns," said Ken-ichi Saitow, lead study author and a professor of chemistry at Hiroshima University.
[...] Aware of the environmental concerns surrounding the current quantum dots, the researchers set out to find a new method for fabricating quantum dots that has a positive environmental impact. Waste rice husks, it turns out, are an excellent source of high-purity silica (SiO2) and value-added Si powder.
[...] The team used a combination of milling, heat treatments, and chemical etching to process the rice husk silica: First, they milled rice husks and extracted silica (SiO2) powders by burning off organic compounds of milled rice husks. Second, they heated the resulting silica powder in an electric furnace to obtain Si powders via a reduction reaction. Third, the product was a purified Si powder that was further reduced to 3 nanometer in size by chemical etching. Finally, its surface was chemically functionalized for high chemical stability and high dispersivity in solvent, with 3 nm crystalline particles to produce the SiQDs that luminesce in the orange-red range with high luminescence efficiency of over 20%.
[...] The team's next steps include developing higher efficiency luminescence in the SiQDs and the LEDs. They will also explore the possibility of producing SiQD LEDs other than the orange-red color they have just created. Looking ahead, the scientists suggest that the method they have developed could be applied to other plants, such as sugar cane bamboo, wheat, barley, or grasses, that contain SiO2. These natural products and their wastes might hold the potential for being transformed into non-toxic optoelectronic devices. Ultimately, the scientists would like to see commercialization of this eco-friendly approach to creating luminescent devices from rice husk waste.
Journal Reference:
Shiho Terada, Honoka Ueda, Taisei Ono & Ken-ichi Saitow, Orange−Red Si Quantum Dot LEDs from Recycled Rice Husks ACS Sustainable Chem. Eng., 10, 5, 2022,
DOI: 10.1021/acssuschemeng.1c04985
(Score: -1, Troll) by Anonymous Coward on Wednesday April 13 2022, @09:13AM (2 children)
This is cool and all. We don't need it, though.
Get rid of all pajeets and chinks. That way we won't have nearly as many rice husks to begin with. Eliminating chinks and pajeets is a much more sustainable solution than concocting some high tech scheme to reuse rice husks.
(Score: -1, Flamebait) by Anonymous Coward on Wednesday April 13 2022, @10:40AM (1 child)
Holy homoerotic fuck you leftists are puerile wusses! Are aristarchus and his probable 50+ sock puppets, DeathMonkey, and Azuma Hazuki so intolerant of anyone whose ideas are different from their own that they feel the need to abuse the spam mod for censorship? Whoever spam modded my post should be promptly modbanned. Whichever leftist pansy was responsible should also be publicly outed and shamed. My post is ontopic and expresses an idea that other readers might not think of. That should qualify for an insightful mod. The spam mod is inappropriate. Are you leftist crybabies so fragile that you can't tolerate anyone having different ideas from your own?
(Score: -1, Flamebait) by Anonymous Coward on Wednesday April 13 2022, @01:17PM
(Score: 3, Funny) by PiMuNu on Wednesday April 13 2022, @09:35AM
... and now I have a good excuse to eat more curry!
(Score: 0) by Anonymous Coward on Wednesday April 13 2022, @11:22AM (3 children)
I assume diatomaceous earth (swimming pool filter sand) would be a much cheaper source of silica.
(Score: 0) by Anonymous Coward on Wednesday April 13 2022, @02:41PM
Not a 'renewable resource'.
Still, high-quality refining is a high-entropy/waste process, and I suppose this work is about more proving that rice husk /could/ be used in the future... when better processes are invented.
(Score: 0) by Anonymous Coward on Wednesday April 13 2022, @04:41PM
it's also used as "fracking sand", pumped underground during fraking to keep those fractures open. good bye silicon, you source for chips and solarpanels ... (woot? ño.chips 'cause the silicon source is pumped underground?)
how's that for " renewable".
i am starting to believe all suggested "energy solutions" first need to go to the oil-financed "energy solution comitee", which first and formost selects " promising" solutions based sole on the possible success of itself staying relevant ...
i hope everybody investing in "green energy" understands the concept of "dog-fooding".
like could a e-car, in a fictional scenario, be used to support and sustain a battery and solarpanel factory etc etc. or are only e-cars successfull that still require input from a fossile fuel?
a " dogfood" co-efficient of 1 would mean no impact if all fossile fuels would disappear tomorrow?
meor on topic: is there enough energy produced in rice husk burning to refine the silicon even? not to mention filtering the pollution of that burning?
(Score: 0) by Anonymous Coward on Wednesday April 13 2022, @04:51PM
I don't think diatomaceous earth, and a lot of other sources, is a high-purity source.
From here [bbc.com]: