Rapid, simultaneous detection of organic chemical pollutants in water is an important issue to solve for protecting human health. This study investigated the possibility of developing an reusable optical sensor capable of selective measurements utilizing a chalcogenide transducer supplemented by a hydrophobic polymer membrane with detection based on evanescent waves in the mid-infrared spectrum. In order to optimise a polyisobutylene hydrophobic film deposited on a chalcogenide waveguide, a zinc selenide prism was utilized as a testbed for performing attenuated total reflection with Fourier-transform infrared spectroscopy. To comply with the levels mentioned in health guidelines, the target detection range in this study was kept rather low, with the concentration range extended from 50 ppb to 100 ppm to cover accidental pollution problems, while targeted hydrocarbons (benzene, toluene, and xylene) were still detected at a concentration of 100 ppb. Infrared measurements in the selected range showed a linear behaviour, with the exception of two constantly reproducible plateau phases around 25 and 80 ppm, which were observable for two polymer film thicknesses of 5 and 10 μm. The polymer was also found to be reusable by regenerating it with water between individual measurements by increasing the water temperature and flow to facilitate reverse exchange kinetics. Given the good conformability of the hydrophobic polymer when coated on chalcogenide photonic circuits and its demonstrated ability to detect organic pollutants in water and to be regenerated afterwards, a microfluidic channel utilising water flow over an evanescent wave optical transducer based on a chalcogenide waveguide and a polyisobutylene (PIB) hydrophobic layer deposited on its surface was successfully fabricated from polydimethylsiloxane by filling a mold prepared CAD and 3D printing techniques.
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http://dx.doi.org/10.1039/d4an00721b | DOI Listing |
Nanophotonics
May 2024
Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Republic of Singapore.
Thin-film coatings offer a scalable optical platform, as compared to nanopatterned films, for various applications including structural coloring, photovoltaics, and sensing. Recently, Fano resonant optical coatings (FROCs) have gained attention. FROCs consist of coupled thin film nanocavities composed of a broadband and a narrowband optical absorber.
View Article and Find Full Text PDFNanophotonics
May 2024
Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716, USA.
Chalcogenide-based nonvolatile phase change materials (PCMs) have a long history of usage, from bulk disk memory to all-optic neuromorphic computing circuits. Being able to perform uniform phase transitions over a subwavelength scale makes PCMs particularly suitable for photonic applications. For switching between nonvolatile states, the conventional chalcogenide phase change materials are brought to a melting temperature to break the covalent bonds.
View Article and Find Full Text PDFAdv Mater
November 2024
Department of Chemistry and Biochemistry, Middlebury College, Middlebury, VT, 05753, USA.
Symmetry control is essential for realizing unconventional properties, such as ferroelectricity, nonlinear optical responses, and complex topological order, thus it holds promise for the design of emerging quantum and photonic systems. Nevertheless, fast and reversible control of symmetry in materials remains a challenge, especially for nanoscale systems. Here, reversible symmetry changes are unveiled in colloidal lead chalcogenide quantum dots on picosecond timescales.
View Article and Find Full Text PDFSmall
November 2024
Department of Chemical and Biological Engineering, Gachon University, 1342 Seongnam-daero, Seongnam, 13120, Republic of Korea.
In recent years, the performance of metal halide perovskite (MHP)-based detectors (photon, biomedical, and X-ray detection) has significantly improved, resulting in higher carrier mobilities, longer carrier diffusion lengths, and excellent absorption coefficients. However, the widespread adoption of halide perovskites has been hindered by issues related to their stability and toxicity. Various strategies have been adopted to address these challenges, focusing on enhancing ambient stability and reducing toxicity by encapsulating MHPs within stable and robust host materials, such as silicon compounds, metal oxides, chalcogenides, and lead-free perovskites.
View Article and Find Full Text PDFInorg Chem
December 2024
State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China.
We report the synthesis and optical characterization of a series of metal chalcogenides, ASiSTe (A = Sr, Ba, Eu), highlighting the metal-atom substitution strategy for the discovery of a high-performance metal chalcogenide-based near-infrared (NIR) scintillator of EuSiSTe. EuSiSTe exhibits exceptionally broad NIR emission with a full width at half-maximum of 210 nm, the largest among all known Eu-based NIR emitters. EuSiSTe has a high light yield of 41697 photons/MeV and excellent resistance to hygroscopicity.
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