New Tortilla LEDs Are Making the World a Little Brighter

by Kathy S. on October 19, 2015

New Tortilla LEDs Are Making the World a Little BrighterUniversity of Utah professors have turned discarded pieces of tortillas into LEDs. The key is food waste. The researchers have synthesized food and beverage waste, including soft drinks, bread and tortillas, into carbon dots (CDs), which ultimately resulted in LEDs.

Quantum dots (QD), or tiny crystals that have luminescent properties and produce light, can be made from many different kinds of materials—some of which are toxic. CDs, or QDs made of carbon, eliminate concerns over toxic waste as the food and beverages themselves are not toxic.

During development, researchers placed the waste into a solvent under pressure and high temperature until the CDs were formed. The waste was heated both directly and indirectly from 30 to 90 minutes. After finding traces of CDs, the researchers illuminated them and monitored their formation and color. Because the dots are only 20 nanometers or smaller in diameter, multiple tests were run to determine the presence of CDs and what optical properties they possess. For comparison, a strand of human hair is approximately 75,000 nanometers in diameter.

Lastly, the CDs were suspended in epoxy resins, heated and hardened for use in LEDs.

According to a report from the U.S. Department of Agriculture, approximately 31 percent of food produced in 2014 was not available for human consumption. This makes the new process both cost-effective and environmentally friendly over the commonly used cadmium selenide, which is toxic when broken down and expensive—about $529 for 25 ml.

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