OLED materials have potential new uses in detecting pesticides for the farming industry

Researchers are set to shine a different kind of light on the farming industry after receiving funding to explore how fluorescent materials can detect the presence of pesticides and herbicides in food production.

Brazil is one of the world’s largest producers and exporters of agricultural products, such as coffee, sugar, tobacco, citrus fruits and grains, but relies heavily on pesticides and herbicides in farming.

Pesticide use in Brazil has grown massively in recent years, with more than 720,000 tonnes of pesticide ingredients sold in 2021, a 5% increase on the year before, leading to high levels of chemical contamination in the produce grown.

A study of 4,600 foods samples found more than half contained pesticide residue and 23% had either more pesticide residue than is allowed or contained pesticides that were not legally allowed to be used on the crop. Other studies show concerningly widespread levels of pesticides in water that meets Brazilian safety standards for drinking.

In a bid to assess the scale and impact of these chemicals in the Brazilian agricultural industry, a £200,000 grant from the Royal Society will bring together experts in environmental contaminant detection with experts in organic light-emitting diodes – more commonly known as OLEDs – which are used in TV and phone screens.

Researchers from Northumbria University in the UK and the Federal University of Santa Catarina in Brazil will work together to develop sensors made from organic light-emitting materials that will show a range of responses when they interact with pesticides, such as glowing, stopping glowing, or changing colour when they react, making it easier to detect their presence on fruit, vegetables and other crops.

They will work with materials which immediately get brighter when they gather and interact with each other, known as aggregation-induced emission and others which emit light at a delayed timescale, known as aggregation-induced delayed fluorescence.

Dr Marc Etherington, an Assistant Professor in Molecular Photophysics at Northumbria University, is an expert in OLEDs. In recent years he has been investigating the light-emitting, light-absorbing and time-delay properties of molecules known as fluorophores. Using a specially developed spectrometer, he has been hopeful of finding new light-based solutions to real-world issues.

He explained: “Brazil is one of the largest global users of pesticides due to its vast agricultural area. This makes it a key country to target to develop new detection methods for pesticides and herbicides being used in the food production industry.

“I’m excited to take the knowledge we have in the specific area of OLEDs and turn it on its head to find a brand-new pathway to solve a global problem.

“If this study works in the way we hope, we believe the science behind it will be applicable for a wide range of industries. There is some huge potential from this work.”

Dr Leonardo Furini from the Federal University of Santa Catarina in Brazil has been developing ways to detect environmental contaminants in food, water and soil. He said: “Brazil is one of the biggest consumers of pesticides in the world and preventing them, herbicides and other toxic elements from permeating through the food chain is of great importance.

“To effectively reduce this contamination of food pathways, early and accurate detection of pesticides and herbicides is necessary.

“Development in this area of pesticide and herbicide detection will have a great impact on the Brazilian economy and will strengthen food security for the local populace and their international exports.”

The project will be supported by HORIBA, which develops cutting-edge fluorescence spectrometers and sensors.

Dr Simon FitzGerald, Head of Science and Technology at HORIBA UK, said: “This project is a brilliant example of taking existing technology and applying it in new ways which may unveil real-world impact.

“We’re delighted to connect the project researchers with experienced HORIBA scientists in both the UK and Brazil to explore how the latest spectroscopic and imaging technologies can be applied.  Technical exchange with the researchers will ensure the most effective use of the latest products and help translate data into meaningful insight.”

The Royal Society has granted the funding to the universities through its ISPF International Collaboration Awards, which supports developing countries. It will enable researchers to travel from Brazil to the UK to work with academic and industry partners, upskill themselves and share their knowledge.