A combined research team in Korea was able to determine a high-selectivity gas sensing material’s reaction mechanism and create the first multi-response high-selectivity gas sensor in the world that can record both optical and electrical readings.
The teams are directed by Professor Hyung Woo Lee of Pusan National University, Dr. Jin Woo Choi of the Department of Energy and Electronic Materials at the Korea Institute of Materials Science (KIMS), and Dr. Han Seul Kim of the Korea Institute of Science and Technology Information (KISTI).
As gas molecules adsorb on the sensing layer’s surface and affect the electrical resistance, existing semiconductor gas sensing materials may detect gas. Since the resistance changes independently of the type of gas, the gas selectivity is low, and in most cases, electrical property change is the only indicator, the present materials are underutilised. The study team built a high-selectivity gas sensor that simultaneously changes colour and resistance after creating a novel material whose crystal structure changes when exposed to a particular gas.
The study team created non-toxic Cs3Cu2I5, a green metal halide thin film material based on copper. Through supercomputer-based simulations, they demonstrated that the material can change reversibly and that water molecules are efficient stimulants for crystal transition. Based on this assumption, the researchers created a sensor device and found that it can successfully identify water molecules. They were able to discriminate between several alcohols with various polarity by combining electrical qualities and colour changes.
The market for gas sensors was valued at $1 billion in 2021 and is anticipated to expand by 7.5% yearly. With the ability to be mass produced, miniaturised, and lightweight, semiconductor gas sensor technology has applications in a variety of industries, including mobile phones, the Internet of Things (IoT), agriculture, and the livestock industry. This technology has significant research significance because it introduced a novel sensor concept and a demonstration case utilising a material with a modifiable crystalline structure.
The principal investigators, Dr. Jin Woo Choi, a senior researcher at KIMS and Dr. Han Seul Kim, a senior researcher at KISTI says that “this research suggests a new direction for development of semiconductor sensor devices and new materials. Due to its response characteristics, the new sensing material is expected to be applied to various industries such as agriculture, livestock, medical, and mobile.”