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Photonic NO2 Gas Sensing with Binaphthyl‐Based Dopants

  • A series of reactive binaphthyl‐diimine‐based dopants is prepared and investigated with respect to their potential for the chiral induction of structural coloration in nematic liquid crystal mixture E7 and the selective photonic sensing of nitrogen dioxide (NO2). Studies of the helical twisting power (HTP) in 4‐cyano‐4′‐pentylbiphenyl (5CB) reveal HTP values as high as 375 µm‐1 and the tremendous impact of structural compatibility and changes of the dihedral binaphthyl angle on the efficiency of the chiral transfer. Detailed investigation of the sensing capabilities of the systems reveals an extraordinarily high selectivity for NO2 and a response to concentrations as low as 100 ppm. The systems show a direct response to the analyte gas leading to a concentration‐dependent shift of the reflectance wavelength of up to several hundred nanometers. Incorporation of copper ions remarkably improves the sensor's properties in terms of sensitivity and selectivity, enabling the tailored tweaking of the system's properties.

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Document Type:Article
Author:Matthias Spengler, Lukas Pschyklenk, Jochen Niemeyer, Peter Kaul, Michael Giese
Parent Title (English):Advanced Optical Materials
Article Number:2001828
Number of pages:8
Place of publication:Weinheim
Publishing Institution:Hochschule Bonn-Rhein-Sieg
Date of first publication:2021/01/25
Copyright:L.P. and P.K. acknowledge the financial support of the project OptoSpin (FKZ 13FH023IX6) by the Federal Ministry of Education and Research of Germany.
Funding:© 2021 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License.
Dedicated in memory of Professor Carsten Schmuck (1968–2019)
Keyword:cholesteric liquid crystals; helical twisting power; nitrogen dioxide; photonic sensing
Departments, institutes and facilities:Fachbereich Angewandte Naturwissenschaften
Institut für Sicherheitsforschung (ISF)
Projects:OptoSpin - IngenieurNachwuchs 2016: Optische Gassensorik mit dotierten Flüssigkristallen verbunden mit koaxialem Elektrospinnen (DE/BMBF/13FH023IX6)
Dewey Decimal Classification (DDC):6 Technik, Medizin, angewandte Wissenschaften / 66 Chemische Verfahrenstechnik / 660 Chemische Verfahrenstechnik
Entry in this database:2021/01/26
Licence (German):License LogoCreative Commons - CC BY - Namensnennung 4.0 International