The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed a next-generation gas sensor technology that uses low-cost and safe LED light to precisely distinguish multiple hazardous gases. Compared with conventional sensors that operate at high temperatures, the new technology consumes significantly less power, offering greater cost efficiency while delivering broad applicability. It is expected to enhance gas safety across industrial settings as well as everyday environments.
Gas sensors currently used in industrial settings typically operate in a high-temperature mode, maintaining temperatures of 200–400°C to enhance reactivity with gas molecules. This approach requires each sensor to be equipped with a micro-heater that continuously heats the device, resulting in high power consumption. Repeated exposure to elevated temperatures also accelerates material degradation, shortening the sensor's operational lifespan.
To address these limitations, gas sensors incorporating ultraviolet (UV) or visible-light LED panels instead of heaters have been proposed. However, commercialization has been constrained by safety and performance concerns. While UV-based sensors offer strong gas reactivity, they pose potential risks of skin damage upon human exposure. In contrast, visible-light LED sensors are safer but exhibit weaker reactivity with gas molecules, making it difficult to detect gases other than nitrogen dioxide.
Dr. Kwon Ki Chang, Principal Research Scientist of the Emerging Material Metrology Group at KRISS, and Nam Gi Baek, a Ph.D. student in the Department of Materials Science and Engineering at Seoul National University, developed a nanostructure in which indium sulfide (In2S3) is thinly coated onto indium oxide (In2O3), dramatically enhancing the performance of visible-light LED-based gas sensors.
The nanostructure, designed in a Type-I heterojunction configuration, acts as an "energy well" that prevents photo-generated charge carriers from dispersing outward and instead concentrates them at the reactive surface when exposed to light. By maximizing the efficiency of light energy utilization, the structure enables immediate interaction with gas molecules using only blue LED illumination without the need for an external heat source.
The research team implemented an electronic nose (E-nose) system by arranging sensors coated with platinum (Pt), palladium (Pd), and gold (Au) nanoparticles on the developed heterojunction structure. Each noble metal catalyst was engineered to respond selectively to specific gases, enabling the system to clearly distinguish hazardous gases such as hydrogen, ammonia, and ethanol even in mixed gas environments much like the human sense of smell.
Performance tests demonstrated that the sensor achieved a limit of detection (LOD) of 201.03 parts per trillion (ppt), representing approximately a 56-fold improvement in sensitivity compared to conventional LED-based sensors. The device also maintained stable operation under 80% humidity and preserved its initial performance over long-term evaluations exceeding 300 days, confirming its strong durability.
The new technology enables a single sensor to identify multiple types of gases while consuming minimal power, making it economically viable for both industrial applications and household use. By detecting various hazardous gases simultaneously with a single installation, it can significantly reduce the cost of sensor deployment in factories and power plants. Thanks to its low maintenance costs, the technology can be readily adopted for real-time air quality monitoring in residential facilities and public spaces.
The sensor operates at room temperature without the need for high-temperature heating, making it well suited for integration into wearable devices such as smartphones and smartwatches. Upon commercialization, the technology could enable user-centered safety services that allow individuals to monitor hazardous environmental conditions in real time along their daily routes and respond immediately to potential gas leak incidents.
Dr. Kwon Ki Chang said the team plans to further optimize catalyst combinations to develop customized intelligent sensors capable of selectively detecting hazardous gases tailored to specific site conditions.
