Korean researchers have developed the world’s first flexible ammonia gas sensor using a low-cost, low-temperature copper bromide film process—marking a major step forward for wearable and environmental sensing technology.
The world’s first highly flexible and ultra-sensitive ammonia sensor based on a low-temperature synthesized copper bromide (CuBr) film, developed by the KIMS research team. Image Credit: Korea Institute of Materials Science (KIMS)
A research team led by Dr. Jongwon Yoon, Dr. Jeongdae Kwon, and Dr. Yonghoon Kim from the Energy & Environmental Materials Research Division at the Korea Institute of Materials Science (KIMS) has developed the world’s first ammonia (NH3) gas sensor using a copper bromide (CuBr) film that can be produced via a simple, low-temperature solution process. This new approach not only delivers flexibility, ultra-sensitivity, and high selectivity but also significantly lowers manufacturing costs.
Ammonia sensors are used to detect airborne ammonia in a range of settings—including environmental monitoring, industrial safety, and medical diagnostics. The CuBr film used in this sensor exhibits a noticeable change in electrical resistance when exposed to ammonia, allowing for the detection of even trace amounts.
Traditionally, creating CuBr films for these sensors required a high-temperature vacuum process above 500 °C, making it difficult to apply them to flexible substrates, which can’t withstand such heat. This also drove up production costs. To overcome these limitations, the team developed a method to form two-dimensional copper nanosheets on a substrate at temperatures below 150 °C—without the need for a vacuum. They then used a straightforward solution-based process to synthesize the copper bromide film, ultimately building a functional ammonia sensor on a plastic substrate.
The result is a highly sensitive sensor capable of detecting ammonia concentrations as low as one part per million (ppm), all while using a low-cost, low-temperature fabrication method. Beyond reducing production costs, the technology opens doors for use in wearable sensors and medical diagnostic tools. Notably, the sensor demonstrated excellent durability and maintained performance even after more than 1000 bending cycles.
The ammonia sensor developed through this study has great potential for expansion into flexible and wearable devices. It can be utilized in a wide range of applications, from indoor air quality monitoring to personal health management. In particular, we expect that it could be applied as a disease diagnosis sensor by attaching it to the human body to analyze exhaled breath.
Dr. Jongwon Yoon, Study Lead Researcher, Korea Institute of Materials Science (KIMS)
The project was carried out in collaboration with Professor Tae-Wook Kim of Jeonbuk National University and Professor Hong Seung Kim of Korea Maritime & Ocean University. It received support from the Global TOP Project under the National Research Council of Science & Technology (NST), the Nano and Material Technology Development Program of the National Research Foundation of Korea (NRF), and foundational research programs at KIMS.
The findings were published online on March 6 in Sensors and Actuators B: Chemical, a leading international journal. The team is now working on scaling up the technology by developing large-area film applications to boost production efficiency.
Journal Reference:
Jin, J., et al. (2025) Low-temperature solution-processed flexible NH3 gas sensors based on porous CuBr films derived from 2D Cu nanosheets. Sensors and Actuators B: Chemical. doi.org/10.1016/j.snb.2025.137567