A printable carbon monoxide sensor could save lives Return to case studies page

A cheap household solution for a silent household killer is being developed at the Materials node of ANFF: the world’s first all-printed organic carbon monoxide sensor.

Carbon monoxide (CO), often called the “silent killer”, takes many thousands of lives every year. It is a colourless, odourless, tasteless and toxic gas produced as a by-product of combustion. It blocks oxygen from getting into the body, which can cause brain damage or death.

Researchers at the Priority Research Centre for Organic Electronics, part of the Materials node, are using organic thin-film transistors embedded with sensing molecules to develop an all-printed organic CO sensor.

In designing the device, the team turned to nature for inspiration when seeking a suitable candidate sensing molecule. They came up with heme, the functional centre of hemoglobin in red-blood cells responsible for shuttling oxygen around the human body. It is this same molecule that CO binds to, preventing the transport of oxygen around the body, when someone has CO poisoning.

“It is well known that CO binds strongly to heme,” said researcher Timothy Sales.

“Heme belongs to a class of molecules called porphyrins, a diverse group of compounds that are easily synthesised and have readily tuneable physical and chemical properties. By altering the structure of a porphyrin we can modify the way it interacts with gases such as CO.”

The group has successfully incorporated their CO-sensing porphyrin molecules into a solution enabling them to be printed. The device, an all-printed organic thin-film transistor with embedded sensing molecules, will alter its electronic properties when exposed to CO gas. The team are aiming for CO detection limits as low as 10 ppm.

The group will soon be moving to pilot-scale production of the sensors with the Materials node’s recent installation of a roll-to-roll organic printer.

“As both the CO-sensing porphyrin molecule and the materials used to fabricate the transistor are solution processed, we are able to print all of the transistor components onto a flexible plastic substrate,” said researcher Nathan Cooling.

“Being able to print CO sensors in large quantities could reduce the unit cost to about that of a chip packet. It would then become affordable to put the sensors on every gas mask, gas stove or oven, or combustion engine car or truck. It could revolutionise the safety industry and potentially save many thousands of lives.”

The team is currently working with industry partners to further develop and commercialise this technology.