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

authored by
Muhammad Shaukat Khan, Hunain Farooq, Christopher Wittmund, Stephen Klimke, Roland Lachmayer, Franz Renz, Bernhard Roth
Abstract

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.

Organisation(s)
Institute of Inorganic Chemistry
Institute of Motion Engineering and Mechanism Design
PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines
Hannover Centre for Optical Technologies (HOT)
Type
Article
Journal
Polymers
Volume
13
Pages
1-10
No. of pages
10
ISSN
2073-4360
Publication date
07.01.2021
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Chemistry(all), Polymers and Plastics
Electronic version(s)
https://doi.org/10.3390/polym13020195 (Access: Open)