Additionally, in developing the high-performance sensor, there is now a new direction for the development of next-generation perovskite-based gas sensors, according to the research team led by Principal Researcher Myungkwan Song of the Energy & Environment Materials Research Division at the Korea Institute of Materials Science (KIMS).
The technology could serve as a key gas-detection solution for improving safety in an emerging hydrogen economy that uses ammonia as an energy carrier.
As a result, ammonia is emerging as an important material in the growing hydrogen economy. However, even small ammonia leaks can be harmful to human health. High-performance sensors capable of immediately detecting trace leaks are therefore essential at storage and transportation facilities, power plants, and industrial sites.
Ammonia Exposure
In particular, exposure to ammonia at concentrations of only several tens of parts per million can affect worker health, creating a need for more sensitive and accurate detection technologies.
Conventional perovskite-based gas sensors can detect ammonia with high sensitivity, but most contain lead (Pb), which is harmful to human health and the environment and limits their potential for commercialization.
To address this issue, the research team developed a lead-free perovskite based on antimony (Sb), known as formamidinium antimony bromide (FA₃Sb₂Br₉), and applied it as the active sensing material in an ammonia gas sensor.
The resulting device achieved environmental advantages and excellent sensing performance.
The sensor reliably detected ammonia at concentrations as low as 1 ppm. Its signal increased consistently as the ammonia concentration rose, demonstrating its ability to quantitatively determine ammonia concentrations.
Eco-friendly perovskite material that transforms into a flower-like shape when exposed to ammonia
Source: Korea Institute of Materials Science (KIMS)
When exposed to ammonia at a concentration of 100 ppm, the sensor responded in just 13 seconds, while its electrical signal increased by as much as 235 percent, demonstrating outstanding sensing performance.
The sensor also showed substantially lower responses to other gases, including methane (CH₄), carbon monoxide (CO), nitrogen oxides (NOₓ), hydrogen (H₂), and methanol (MeOH), confirming its high selectivity for ammonia.
After undergoing storage for two months, the sensor retained approximately 97 percent of its initial performance, demonstrating excellent long-term stability. It can also end up fabricated through a simple spin-coating process using solution-based materials, making it well suited for large-area production and lower-cost manufacturing.
One of the study’s most significant achievements was the identification of a new ammonia-sensing mechanism, in addition to the development of the high-performance sensor.
Sensor Signal
Conventional explanations have generally attributed the electrical signals of ammonia sensors to ammonia molecules adsorbing onto the surface of the sensing material. The research team found, however, ammonia molecules reversibly intercalate into the perovskite material and induce p-type doping. This process increases the material’s electrical conductivity and generates the sensor signal.
The mechanism differs fundamentally from conventional surface adsorption-based sensing and provides a new materials-design principle for improving the sensitivity and selectivity of future perovskite gas sensors.
The technology could end up used as a safety-monitoring sensor for the early detection of trace gas leaks at power plants and ships that use ammonia as a fuel or hydrogen carrier.
It could also deploy at ammonia production, storage, and transportation facilities, as well as fertilizer and chemical plants.
Because the sensor can end up produced through a relatively simple solution process, the technology is suitable for large-area fabrication and mass production. It could ultimately end up developed into various formats, including portable detectors, sensors attached directly to pipelines, and real-time hazardous-gas monitoring systems.
The technology could contribute to the domestic production of high-performance gas sensors currently heavily dependent on imports, while reducing maintenance and operational costs. It could also strengthen the competitiveness of Korea’s materials and sensor industries in the rapidly growing hydrogen and ammonia energy markets.
“This study is significant not only because we developed a highly sensitive ammonia sensor using an environmentally friendlier, lead-free perovskite, but also because we identified its sensing mechanism at the atomic level,” Song said. “We expect this technology to widely apply to safety management for hydrogen- and ammonia-based energy infrastructure, as well as hazardous-gas monitoring at industrial sites.”