Materials scientists have devised an eco-friendly way to produce light-emitting graphene quantum dots (GQDs) from waste dry-cell batteries1.
The GQDs, which have optical properties, look promising for imaging and sensing applications. Such a use of waste batteries, the researchers say, will also offer a way to recycle spent batteries.
Fifty-two per cent of waste dry-cell batteries end up corroding and leaching toxic heavy metals that are harmful to human health.
To find a way to avert this, the scientists from the CSIR-Advanced Materials and Processes Research Institute (AMPRI) in Bhopal, India, extracted graphite rods from waste dry-cell batteries. They then electrochemically treated the rods, converting them into nanosized GQDs.
The average size of the GQDs was found to be between 6 and 10nm. To explore their optical properties, the researchers, led by Raju Khan, exposed the dots to ultraviolet light. Such exposure made the dots absorb the UV light and then emit green light.
The dots with a large surface concentration also showed high electrical responses. Such optical and electrical properties of the dots suggest that they could potentially be used for a wide range of sensing applications.
“This method of producing the GQDs is industrially scalable and could find uses in multimodal image-guided cancer therapy and other therapies and diagnostic tools,” says Khan.
