Novel Opto-Chemical Sensor Technology for Dangerous Environments

Published on May 17, 2012 at 9:22 AM

By Kalwinder Kaur

Researchers in the EU-funded Dotsense project have developed a new optical sensor that is more safe and sensitive than current chemical sensors.

New optical sensor can 'see' dangerous chemicals © Shutterstock

They used quantum dots and nanowires made from chemically stable semiconductor materials of the group III-nitride semiconductor system to produce the sensors.

Sensors are required in harsh liquid and gaseous environments to monitor the acidity, composition or leakage. Many methods of monitoring have been used for monitoring chemicals, including the use of nanowires. But they involve electricity as measurements are based on electrical conductivity. Combination of certain liquids and gases with electricity may be dangerous. The new sensors are optical and they are based on chemically stable semiconductor materials that display variations in photoluminescence properties when changes to the chemical environment take place.

The researchers used nanowires comprising of an array of a billion InGaN or GaN 'nanodisks' or 'quantum dots'. These wires were placed in the liquid/gaseous environment to be monitored. An excitation light was shone which induced the photoluminescence properties of the nanostructures to change. This modification is based on the specific chemicals in the environment. This leads to variation in the transducer’s light intensity, which can be read using common photodetectors.

The opto-chemical sensor technology could be used in aerospace applications for monitoring fuel, gas leaks and hydraulic fluid on aircraft in a safe manner. The Dotsense project primarily aimed to develop chemical sensors without electrical contacts. The opto-chemical sensor they developed exhibited more sensitivity when compared to electrical sensors. This increases its potential uses and could be used for detecting gases in healthcare applications, home smoke alarms and industrial environments.

Though key challenges have been overcome in this project, more research is required for commercialization of this technology.