Ionogel-based composite material for CO2 sensing deposited on a chemiresistive transducer

A novel miniaturized carbon dioxide (CO2) sensor based on an IDE transducer is described and characterized. The CO2 sensor based on different semiconducting metal oxide and ionogel composites films deposited by ink-jet printing. The sensor is operated as a simple chemiresistor. The sensors were investigated under trace gas exposure (CO2, NO2, CO and humidity). The CO2 sensitivity is found to be exceptionally high and the sensing mechanism is supposed to be entirely different compared to those of the components of the composite

FT-IR Coupled Goniometer Setup for Characterization of the Spatial and Spectral Emission of IR-Sources

We present a FT-IR coupled goniometer setup, which allows the simultaneous spatial and spectral characterization of optical components used in non-dispersive infrared gas sensor systems. The performance of the laboratory setup is demonstrated by comparing reflector and Fresnel lens equipped thermal infrared radiation sources. We show that even the simplest binary Fresnel lenses, when optimally designed, can achieve a thinner emission angle than parabolic mirrors at comparable radiation intensities

Filterrotationsspektrometer für den Nachweis von Ethen im ppb-Bereich

Ethen ist eines der wichtigsten Phytohormone im Reifungsprozess klimakterischer Früchte. Die Menge des emittierten Ethens liefert Informationen über den aktuellen Reifezustand dieser Früchte. Deshalb kann es in der Lieferkette für die Umsetzung fortschrittlicher Prozesse, wie dem First-Expired-First-Out-Prozess (FEFO), eingesetzt werden. Diese Arbeit beschreibt den aktuellen Stand der Entwicklung eines kostengünstigen Filterrotationsspektrometers für den Nachweis von Ethen in der klimakterischen Reifephase von Früchten. Das Spektrometer basiert im Wesentlichen auf Komponenten, die auch in nichtdispersiven Infrarotsensoren (NDIR) zum Einsatz kommen. Durch eine modellbasierte Auswertung der Spektren konnte die Stabilität eines ersten Laborprototyps gegenüber klassischen NDIR-Sensoren deutlich verbessert werden. In Verbindung mit einer optimierten Langwegzelle konnte die Nachweisgrenze bis auf 150 ppb reduziert werden

Optimization of platinum adhesion in electrochemical etching process for multi-sensor systems

This paper presents optimized process conditions to overcome the problem of poor adhesion between platinum (Pt) metal layer and substrates in an electrochemical etching process required for forming porous silicon. Good Pt adhesion on silicon and silicon nitride substrate is obtained by respectively, applying 20 nm Ta and 20 nm/20 nm tantalum/polysilicon layer between them to improve adhesion and prevent the diffusion of Pt to the substrates. The best anneal conditions for the metallization systems are 590 °C, 30 min, 18 °C/min in a N2 ambient furnace. The optimized process is used for the realization of a Pt metallization-based multi-sensor system

Evaluation of a Colorimetric Sensor System for Early Fire Detection

The use of colorimetric reactions as a sensitive, selective and low-cost method for the detection of fire related gases is evaluated in this work. As the most relevant fire gas carbon monoxide CO is addressed in the first place. A rhodium-based metal-organic complex has been selected, which a colorimetric material sensitive for CO. For the optical readout a compact setup has been developed which provides the option for spectroscopy in transmission and attenuated total reflection in parallel. The detection of CO in concentrations relevant for fire detection has been demonstrated in synthetic gas mixtures as well as in real fire gas

Improvement Methods for Colorimetric Gas Sensor for Use in Indoor Livestock Farming

Different published colorimetric sensors were investigated with the ultimate goal to develop a colorimetric sensor for a closed livestock farm, applicable in a rough environment. The methods were investigated to improve the lack of sensitivity, roughness, and reproduction of colorimetric sensors. The methods investigated varied from changing matrices, changing substrates, treatment of the substrates, and investigation of the distribution by camera of the chemical thin layer and investigation on temperature, water and cross interference of several other gases in the livestock gas matrix. Results showed that with changing several important parameters, other than only the choice of a color indicator results in a serious improvement of the sensor specification and an improved performance necessary for the rough circumstances in livestock farming