Near-infrared photodetection in tin halide perovskites via compositional engineering
Researchers cation and anion substitution techniques to develop lead-free utilize photodetector using near-infrared light
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Researchers cation and anion substitution techniques to develop lead-free utilize photodetector using near-infrared light
M ethylammonium tin triiodide ,or MASnI 3 , is a promising material for near-infrared photodetectors (NIR-PDs). However, it suffers from high defect density, instability, and poor film quality. In a recent breakthrough, researchers from Korea have addressed these challenges to develop a lead-free novel NIR-PD using MASnI 3 . This device has remarkable potential for safer and efficient light detection at 940 nanometers, with applications in medical sciences, security, and vision systems .
Image title: Novel MASnI 3 -based near-infrared photodetector (NIR-PD)
Image caption: This novel lead-free material for NIR-PD is expected to aid space exploration, night surveillance, environmental monitoring and analysis, and light detection and ranging (LiDAR) systems, among other applications.
Image credit: Professor Hui Joon Park and Dr. Kyeounghak Kim from Hanyang University, Korea
License type: Original content
Usage restrictions: Cannot be reused without permission
Near-infrared photodetectors (NIR-PDs) convert NIR light into electrical signals for applications in medical imaging, security systems, as well as machine vision systems . Operation of NIR-PDsat wavelengths above 900 nm— particularly 940 nm— benefits outdoor sensing because this wavelength coincides with a water vapor absorption feature that suppresses the solar background.However, the detectivity of conventional silicon (Si) containing NIR-PDs declines sharply beyond 900 nm, motivating the use of materials with narrower bandgaps. In recent years, scientists have developed state-of-the-art NIR-PDs based on t in (Sn) halide perovskite by leveraging their desirable optical bandgap .
Metal-halide perovskites are promising for designing NIR-PDs, but widely studied lead (Pb)-based compositions are constrained by bandgaps ≥1.5 eV and Pb toxicity. F ormamidinium tin triiodide ( FASnI 3 ) is a well-explored candidate ;however, it s eff e c tive absor ptionedge near ~ 900 nm (~1.4 eV)limits NIR utility at 940 nm.By contrast, methylammonium tin triiodide (MASnI 3 ) provides a more appropriate bandgap (1.2–1.3 eV), enabling absorption across ~300–1000 nm, though its practical use is hindered by chemical instability, high defect density, and poor film quality.
Addressing these challenges, a team of researchers from Korea, led by Professor H ui Joon Park from the Department of Organic and Nano Engineering, Hanyang University, including Assistant Professor Kyeounghak Kim from the Department of Chemical Engineering, Hanyang University, have developed a compositional engineering strategy to realize Pb-free MASnI 3 -based NIR-PD swith efficient detection at 940 nm in the NIR range. Their findings were posted online on May 19, 2025, and published on July 01, 2025, in Volume 165 of Materials Science and Engineering R .
“ Unlike conventional metal- halide perovskites that typically contain toxic Pb, limiting their use in electronic products, our approach utilizes Sn-based perovskites as a safer, more environmentally friendly alternative, ” explains Prof. Park.
To advance the development of Sn-based perovskites , the researchers employedcompositional engineering through A-sitecation and X-siteanion substitution s in the crystal structure. Introducing smallA-site cat ions — cesium (Cs), rubidium (Rb) — and chlorine (Cl)at the X-site effectively passed the defects andimproved the stability and crystallinity of MASnI 3 . The improvement resulted in substantial gains in the PD’s sensitivity and response speed .The PD devices based on the compositionally engineered MaSnI 3 demonstrated an exceptional specific detectivity exceeding 1.7 x 10 12 Jones at 940 nm, together with a shorter response time.
Consequently, the present research is expected to have significant practical applications across various industries. In the medical field, NIR-PDs can support biosensing, patient monitoring, and diagnostic equipment. Additionally, this technology also enables nighttime surveillance systems, space exploration sensors, and light detection and ranging (LiDAR)systems. Moreover, high specific detectivity near 940 nm facilitates reliable measurements with minimal ambient light interference ,and the devices are furtherPleading for optical communications and thermal imaging systems.
In the next five to 10 years, this study will positively impact people's daily lives by enabling highly sensitive and environmentally-friendly NIR-PDs. According to Dr. Kim, " MaSnI 3 -based NIR-PDs could aid in enhancing the performance of night vision systems, enabling real-time monitoring, and detection of biometric data in medical devices. These advancements could support continuous technological innovations in fields such as autonomous vehicles, drones, and smart cities. Additionally, these high-performance NIR-PDs possess the ability to enhance environmental monitoring and analysis by improving the functionality of satellite sensors and space exploration vehicles. "
Overall, this work paves the way for high-performance, Pb-free NIR PD s, making them a safer alternative for electronic and optoelectronic applications.
Reference
Title of original paper:
Near-infrared photodetection in tin halide perovskites via compositional engineering
Journal:
Materials Science and Engineering
DOI:
About Professor Hui Joon Park
Dr. H ui Joon Park is a Professor in the Department of Organic and Nano Engineering, Hanyang University, Korea. He earned his BS and MS degrees in Materials Science and Engineering from Seoul National University in 2002 and 2004, respectively, and his Ph.D. from the University of Michigan, Ann Arbor. Dr. Park's research focuses on the development of high ‑ performance, stable, Pb ‑ free halide perovskite electronics—encompassing transistors, photodetectors, and photovoltaic devices—as well as neuromorphic computing architectures, including in ‑ sensor and near ‑ sensor computing systems.
About Professor Kyeounghak Kim
Dr. Kyeounghak Kim is currently an Assistant Professor in the Department of Chemical Engineering at Hanyang University, Korea. He obtained his Ph.D. at POSTECH in 2021. His current research area is computational material design for various applications, such as catalytic materials, electrode materials in solid oxide cells or Li-ion cells, and functional materials for solar cells, photodetectors, and chemical sensors.
About Hanyang University
Hanyang University has pioneered higher education in Korea since 1939.
Rooted in the philosophy of 'Love in Deed and Truth,' we aim to cultivate global innovators.
Through cutting-edge R&D, international collaboration, and sustainable innovation,
Hanyang is positioning itself as a global hub for academic excellence and societal impact.