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Multimodal Gas Sensor Detecting Hydroxyl Groups with Phase Transition Based on Eco‐Friendly Lead‐Free Metal Halides
Author(s) -
Lee Daseul,
Lee SeungJea,
Kim Jae Ho,
Park Juyun,
Kang YongCheol,
Song Myungkwan,
Lee Hyung Woo,
Kim Han Seul,
Choi Jin Woo
Publication year - 2022
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202202207
Subject(s) - halide , responsivity , materials science , phase transition , phase (matter) , relative humidity , reactivity (psychology) , selectivity , polarity (international relations) , carbon dioxide sensor , metal , ion , analytical chemistry (journal) , photochemistry , inorganic chemistry , optoelectronics , photodetector , catalysis , chemistry , carbon dioxide , organic chemistry , thermodynamics , physics , cell , metallurgy , medicine , biochemistry , alternative medicine , pathology
An electrical and optical responsive chemical‐semiconductor gas sensor is developed using Cu(I) halides with a phase transition mechanism. Cu(I) materials exhibit reversible phase transitions between the Cs 3 Cu 2 I 5 and CsCu 2 I 3 with different properties, owing to the formation/destruction of the Cs–I and Cu–Cu bonding when the hydroxyl groups are attached/detached. Among various toxic and atmospheric gases, a Cu(I)‐based gas sensor has high selectivity in detecting the hydroxyl group, and the highest sensitivity to water. The reactivity is determined by the polarity, where water with the largest polarity has the strongest attraction for Cu + and I − ions, letting phase transition occur easily. The multimodal sensor red‐shifts emission from 445 to 575 nm when it detects hydroxyl gas, and the moisture‐sensitive sensor visually confirms response to breaths in less than 5 s and recovery in the air in less than 30 s. The gas sensor can operate at room temperature while applying a constant bias voltage of 1 V, and it also shows excellent sensitivity in a relative humidity range of 15–75%. Furthermore, the sensor maintained ≈90% of its initial responsivity over 1 year.