The 2023 Nobel Prize in Chemistry was focused on quantum dots — objects so tiny, they’re controlled by the strange and complicated rules of quantum physics. Many quantum dots utilized in electronics are made out of toxic substances, but their nontoxic counterparts are actually being developed and explored for uses in medicine and within the environment. One team of researchers is specializing in carbon- and sulfur-based quantum dots, using them to create safer invisible inks and to assist decontaminate water supplies.
The researchers will present their results today on the spring meeting of the American Chemical Society (ACS).
Quantum dots are synthetic nanometer-scale semiconductor crystals that emit light. They’re utilized in applications similar to electronics displays and solar cells. “Many conventional quantum dots are toxic, because they’re derived from heavy metals,” explains Md Palashuddin Sk, an assistant professor of chemistry at Aligarh Muslim University in India. “So, we’re working on nonmetallic quantum dots because they’re environmentally friendly and may be utilized in biological applications.”
Quantum dots are tiny — normally only tens of atoms in diameter. Because they’re so small, their properties are controlled by quantum effects, which makes them act a bit of strangely in comparison with larger objects. Namely, they emit light otherwise than one might expect; for instance, gold materials appear blue on this scale. Nonmetallic quantum dots exhibit the identical effect and have been explored by other researchers as a tool for bioimaging. Palashuddin has focused on designing carbon- and sulfur-based quantum dots (Cdots and Sdots, respectively) for a wide range of other applications.
“Carbon and sulfur are very abundant, cost-effective materials, they usually can easily be synthesized into quantum dots,” he says. “You may make carbon dots from waste materials, then use them for removing pollutants — they are a technique to make the method come full circle.”
Palashuddin has already put Cdots and Sdots to work in a wide range of ways, though each are relatively recent discoveries. Though small, the dots have a big surface area, which might easily be functionalized to adapt the dots for various applications. Previously, the team designed dots that shined different colours, depending on which contaminants they encountered. That meant they may help discover contaminants — similar to lead, cobalt and chromium — in a water sample without leaching any recent metals from the dots themselves.
Along with identifying contaminants, Cdots can assist break down pollutants similar to pesticides and dyes in water. In a single project, Palashuddin and collaborator Amaresh Kumar Sahoo, an assistant professor who studies nanobiotechnology on the Indian Institute of Information Technology, formed Cdots from potato peels after which mounted them on microscopic robots designed to focus on and degrade toxic dyes in samples simulating polluted water.
The team has also developed methods to remove contaminants from water entirely, quite than simply identifying or degrading them. They’ve specially designed Cdots to sop up automotive oil and are currently exploring a Cdot-based filter system to assist treat oil spills.
Next, the researchers plan to place their laboratory findings to work in the sector, possibly in a project focused on the Yamuna River. This river runs directly through Latest Delhi and is famously contaminated, especially in additional populated areas. Palashuddin hopes to make use of his team’s nonmetallic dots to discover and separate the varied pollutants within the river, including pesticides, surfactants, metal ions, antibiotics and dyes. Ideally, the dots will likely be functionalized to grab as lots of these different contaminants on their surfaces as possible, in order that they can then be easily removed.
The potential uses for nonmetallic dots don’t just end with water treatment, though. Palashuddin and colleagues are currently investigating uses that would align more closely with traditional, metal-based dots, but without the toxicity concerns. For example, some light-emitting quantum dots developed by the team might be included in invisible inks to assist prevent counterfeiting, or incorporated into light-emitting devices, including television screens.
The team hopes that their work can assist broaden the uses for nonmetallic quantum dots and put their unique properties to work within the environment.
The research was funded by the Science and Engineering Research Board and the University Grants Commission of the Government of India.
