Gas sensing properties of a maghemite-coupled porphyrin thin film–based optical waveguide sensor

Abstract

This study concerns the development of a maghemite (γ-Fe2O3)-coupled tetra sulfophenyl porphyrin (TSPP) thin film–based optical waveguide (OWG) sensor (TSPP-γ-Fe2O3-OWG) for the detection of ethylenediamine (EDA). For ease of manufacture, we fabricated sensors using a spin-coating technique, and characterized their response based on their ultraviolet-visible (UV-vis) absorption spectra and the response intensity of OWG sensor. We have observed significant changes in the location of the peaks in the sensor’s UV-vis absorption spectra after exposed to EDA gas, indicating aggregation of TSPP. Optical characterization confirmed that the combination of TSPP with maghemite (TSPP-γ-Fe2O3-OWG) had improved device response, with twice as high as those of the acid-treated TSPP-OWG sensor, and 30 times higher than that of the pure γ-Fe2O3-OWG sensor. At ambient temperature, the composite sensor exhibited a linear response to EDA gas in the concentration range of 0.1–1000 ppm with signal-to-noise ratio (S/N) 8.33, confirming that the improved stability of the composite TSPP-γ-Fe2O3 thin-film OWG enables the detection of trace amounts of gas with high sensitivity and selectivity.

Effect on Improving CO2 Sensor Properties: Combination of HPTS and γ-Fe2O3@ZnO Bioactive Glass

“…Iron oxide, commonly known as hematite (α-Fe 2 O 3 ), magnetite (Fe 3 O 4 ), and/or maghemite (γ-Fe 2 O 3 ), offers several benefits, including chemical and biological stability, low toxicity, a superparamagnetic characteristic, and low cost for large-scale synthesis that make it well suited for sensor applications . The choice of the shell material and its properties are critical considerations to achieve the desired performance and functionality of the Fe 2 O 3 nanoparticles in biomedical imaging, drug delivery, magnetic separation, environmental remediation, and catalysis applications . Au, MoS 2 , MnO 2 , SiO 2 , ZnO, and TiO 2 have all been used for this purpose.…”

“… 14 The choice of the shell material and its properties are critical considerations to achieve the desired performance and functionality of the Fe 2 O 3 nanoparticles in biomedical imaging, drug delivery, magnetic separation, environmental remediation, and catalysis applications. 15 Au, 16 MoS 2 , 17 MnO 2 , 18 SiO 2 , 19 ZnO, 20 and TiO 2 21 have all been used for this purpose. Ahadpour Shal et al reported that the coprecipitation technique was used to make core–shell-type magnetite Fe 3 O 4 @ZnO nanostructures.…”