The Korea Research Institute of Standards and Science (KRISS) has developed a next-generation gas sensor technology that can precisely identify multiple types of hazardous gases using affordable and safe LED light.
The technology consumes less power than conventional sensors that operate at high temperatures, making it more economical. Its superior versatility is expected to significantly enhance gas safety across industrial sites and everyday life.
Gas sensors currently used in industrial settings primarily employ a "high-temperature operation method" that requires maintaining temperatures of 200-400°C to increase reactivity with gas molecules. This approach requires attaching micro-heaters to each sensor for constant heating, resulting in high power consumption and rapid material wear from repeated heat exposure.
To address these issues, gas sensors using ultraviolet or visible light LED panels instead of heaters have been proposed, but commercialization has been limited due to safety and performance concerns. While ultraviolet methods offer good gas reactivity, they pose skin damage risks upon human exposure. Visible light LED methods are safe but have weak reactivity with gas molecules, making it difficult to detect gases other than nitrogen dioxide.
KRISS Principal Researcher Kwon Ki-chang from the Advanced Materials Measurement Group and Seoul National University doctoral candidate Nam Ki-baek developed a nanostructure with a thin coating of indium sulfide (In2S3) on indium oxide (In2O3), dramatically improving visible light LED-based gas sensor performance.
The "Type-I heterojunction" nanostructure developed by the research team functions as an "energy well" that concentrates electrical charges generated by light toward the reactive surface rather than allowing them to scatter. By maximizing light energy efficiency, the team created a detection structure that can react immediately with gas molecules using only blue LED light without a separate heat source.
The researchers implemented an "electronic nose (E-nose)" function by arranging sensors coated with platinum (Pt), palladium (Pd), and gold (Au) nanoparticles on the heterojunction structure. Each precious metal catalyst is designed to react sensitively only to specific gases, enabling clear identification of hazardous gases including hydrogen, ammonia, and ethanol even in environments with mixed gases—similar to the human nose.
Performance tests showed the developed sensor's limit of detection (LOD) reached 201.03 ppt (parts per trillion), representing approximately 56 times greater sensitivity than existing LED-based sensors. The sensor also demonstrated excellent durability, operating stably in 80% humidity environments and maintaining initial performance over 300 days of long-term evaluation.
The technology can identify multiple gas types with a single sensor and consumes little power, making it economically viable for both industrial sites and residential applications. A single installation can simultaneously detect multiple hazardous gases, reducing sensor deployment costs at factories and power plants.
The low maintenance costs make the technology easily deployable in real-time air quality management systems for residential facilities and public spaces where adoption was previously difficult.
The sensor operates at room temperature without high-temperature heating processes, making it suitable for integration into smartphones, smartwatches, and other wearable devices. Once commercialized, the technology could enable lifestyle-integrated safety services allowing users to monitor hazardous environments in real-time along their travel routes and respond immediately to gas leak incidents.
"We plan to optimize catalyst combinations to develop customized intelligent sensors that selectively detect hazardous gases suited to specific site characteristics," said KRISS Principal Researcher Kwon Ki-chang.
The research was published in December in Small (IF: 12.1), an academic journal in the nano and sensor field.