# Lead-free antimony-based perovskite enables highly sensitive ammonia detection down to 1 ppm

# Newly identified sensing mechanism reveals reversible ammonia intercalation and enhanced electrical conductivity, offering potential for safety monitoring in hydrogen and ammonia energy infrastructure

CHANGWON, South Korea — A research team led by Principal Researcher Myungkwan Song of the Energy & Environment Materials Research Division at the Korea Institute of Materials Science (KIMS), headed by President Chul-jin Choi, has developed an ultrasensitive ammonia gas sensor using an environmentally friendly, lead-free perovskite material. The research was conducted in collaboration with teams led by Professor Hyung Woo Lee of Pusan National University, Professor Youngho Kang of Incheon National University, and Professor Jincheol Kim of Macquarie University in Australia. In addition to developing the high-performance sensor, the researchers elucidated, for the first time, the mechanism by which it detects ammonia, providing a new direction for the development of next-generation perovskite-based gas sensors. The technology is expected to serve as a key gas-detection solution for improving safety in an emerging hydrogen economy that uses ammonia as an energy carrier.

Ammonia has recently attracted significant attention as a next-generation hydrogen carrier because it can facilitate the storage and transportation of hydrogen, which is otherwise difficult to handle. 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. 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 both 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. 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%, 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 being stored for two months, the sensor retained approximately 97% of its initial performance, demonstrating excellent long-term stability. It can also be 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. 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, that 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 be 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 be deployed at ammonia production, storage, and transportation facilities, as well as fertilizer and chemical plants. Because the sensor can be produced through a relatively simple solution process, the technology is suitable for large-area fabrication and mass production. It could ultimately be developed into various formats, including portable detectors, sensors attached directly to pipelines, and real-time hazardous-gas monitoring systems. The technology is expected to contribute to the domestic production of high-performance gas sensors that are 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,” said Myungkwan Song, principal researcher and project leader at KIMS. “We expect this technology to be widely applied to safety management for hydrogen- and ammonia-based energy infrastructure, as well as hazardous-gas monitoring at industrial sites,” he added.

The research was supported by the Ministry of Science and ICT through the KIMS Institutional Research Program, the Global Leading Research Center Program of the National Research Foundation of Korea, and the Global TOP Strategic Research Group Program of the National Research Council of Science & Technology. The findings were published online on July 27, 2026, in Small Structures (Impact Factor: 8.9), a leading international journal in materials science.

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About Korea Institute of Materials Science(KIMS)

KIMS is a non-profit government-funded research institute under the Ministry of Science and ICT of the Republic of Korea. As the only institute specializing in comprehensive materials technologies in Korea, KIMS has contributed to Korean industry by carrying out a wide range of activities related to materials science including R&D, inspection, testing&evaluation, and technology support.