TY - JOUR

T1 - Polymer optical waveguide sensor based on fe-amino-triazole complex molecular switches

AU - Khan, Muhammad Shaukat

AU - Farooq, Hunain

AU - Wittmund, Christopher

AU - Klimke, Stephen

AU - Lachmayer, Roland

AU - Renz, Franz

AU - Roth, Bernhard

N1 - Funding Information: Funding: We acknowledge the financial support provided by the Lower Saxony Ministry of Science and Culture (MWK) under PhD Program Tailored Light and the German Research Foundation DFG under Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). The publication of this article was funded by the Open Access Fund of Leibniz Universität Hannover.

PY - 2021/1/7

Y1 - 2021/1/7

N2 - We report on a polymer-waveguide-based temperature sensing system relying on switch-able molecular complexes. The polymer waveguide cladding is fabricated using a maskless litho-graphic optical system and replicated onto polymer material (i.e., PMMA) using a hot embossing device. An iron-amino-triazole molecular complex material (i.e., [Fe(Htrz)2.85 (NH2-trz)0.15 ](ClO4)2) is used to sense changes in ambient temperature. For this purpose, the core of the waveguide is filled with a mixture of core material (NOA68), and the molecular complex using doctor blading and UV curing is applied for solidification. The absorption spectrum of the molecular complex in the UV/VIS light range features two prominent absorption bands in the low-spin state. As temperature approaches room temperature, a spin-crossover transition occurs, and the molecular complex changes its color (i.e. spectral properties) from violet-pink to white. The measurement of the optical power transmitted through the waveguide as a function of temperature exhibits a memory effect with a hysteresis width of approx. 12◦ C and sensitivity of 0.08 mW/◦ C. This enables optical rather than electronic temperature detection in environments where electromagnetic interference might influence the measurements.

AB - We report on a polymer-waveguide-based temperature sensing system relying on switch-able molecular complexes. The polymer waveguide cladding is fabricated using a maskless litho-graphic optical system and replicated onto polymer material (i.e., PMMA) using a hot embossing device. An iron-amino-triazole molecular complex material (i.e., [Fe(Htrz)2.85 (NH2-trz)0.15 ](ClO4)2) is used to sense changes in ambient temperature. For this purpose, the core of the waveguide is filled with a mixture of core material (NOA68), and the molecular complex using doctor blading and UV curing is applied for solidification. The absorption spectrum of the molecular complex in the UV/VIS light range features two prominent absorption bands in the low-spin state. As temperature approaches room temperature, a spin-crossover transition occurs, and the molecular complex changes its color (i.e. spectral properties) from violet-pink to white. The measurement of the optical power transmitted through the waveguide as a function of temperature exhibits a memory effect with a hysteresis width of approx. 12◦ C and sensitivity of 0.08 mW/◦ C. This enables optical rather than electronic temperature detection in environments where electromagnetic interference might influence the measurements.

KW - Hot embossing

KW - Iron-triazole complexes

KW - Maskless lithography

KW - Memory effect

KW - Microfabrication

KW - Polymer optical sensor

KW - Temperature sensor

UR - http://www.scopus.com/inward/record.url?scp=85099153490&partnerID=8YFLogxK

U2 - 10.3390/polym13020195

DO - 10.3390/polym13020195

M3 - Article

AN - SCOPUS:85099153490

VL - 13

SP - 1

EP - 10

JO - Polymers

JF - Polymers

SN - 2073-4360

IS - 2

M1 - 195

ER -