Stomata‐Inspired Photomechanical Ion Nanochannels Modified by Azobenzene Composites |
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Authors: | Kyoung‐Yong Chun Young Jun Son Sunghwan Jo Chang‐Soo Han |
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Affiliation: | 1. School of Mechanical Engineering, College of Engineering, Korea University, Seongbuk‐Gu, Seoul, Republic of Korea;2. Institute of Advanced Machinery Design Technology, Korea University, Seongbuk‐Gu, Seoul, Republic of Korea;3. Division of Micro/Nano System, College of Engineering, Korea University, Seongbuk‐Gu, Seoul, Republic of Korea |
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Abstract: | A low‐powered and highly selective photomechanical sensor system mimicking stomata in the epidermis of leaves harvested from nature is demonstrated. This device uses a light‐responsive composite consisting of 4‐amino‐1,1′‐azobenzene‐3,4′‐disulfonic acid monosodium salt (AZO) and poly(diallyldimethylammonium chloride) (PDDA) coated on a membrane with tens of nanometer‐size pores. The ionic current change through the pore channels as a function of pore size variation is then measured. The tran–cis isomerism of AZO–PDDA during light irradiation and the operation mechanism of photomechanical ion channel sensor are discussed and analyzed using UV–vis spectroscopy and atomic force microscopy analysis. It presents the discriminative current levels to the different light wavelengths. The response time of the photoreceptor is about 0.2 s and it consumes very low operating power (≈15 nW) at 0.1 V bias. In addition, it is found that the change of the pore diameter during the light irradiation is due to the photomechanical effect, which is capable of distinguishing light intensity and wavelength. |
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Keywords: | azobenzene ion channels photomechanical sensors pore actuation stomata |
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