Exploring Optical and Electrical Gas Detection Based on Zinc-Tetraphenylporphyrin Sensitizer

TL;DR

This study develops optical and electrical gas sensors using zinc-tetraphenylporphyrin, demonstrating high sensitivity and strong chemical adsorption detection of NO2 gas with different techniques.

Contribution

It introduces a comparative analysis of optical and electrical sensors based on ZnTPP, highlighting the superior SNR of the optical waveguide sensor for NO2 detection.

Findings

Optical waveguide sensor achieves SNR of 109.6 for 1 ppm NO2.

UV-vis and electrical sensors show lower SNRs compared to optical.

FT-IR and UV-vis spectra confirm strong chemical adsorption of NO2 on ZnTPP.

Abstract

We developed optical waveguide (OWG), ultraviolet-visible spectrophotometry (UV-vis), and electrically operated gas sensors by utilizing zinc-tetraphenylporphyrin (ZnTPP) as sensitizer. Strikingly, ZnTPP thin-film/K+-exchanged glass optical waveguide (OWG) sensing element exhibits a superior signal-to-noise ratio (SNR) of 109.6 upon 1 ppm NO2 gas injection, which is 29.5 and 3.8 times larger than that of UV-vis (absorbance at wavelength of 438 nm) and ZnTPP electrical sensing elements prepared on an alumina ceramic tube, respectively. Further results on Fourier Infrared spectra (FT-IR) and UV-vis spectra, confirm a strong chemical adsorption of NO2 gas on ZnTPP. Therefore, our studies highlight the selection of suitable detection technique for analyte sensing with ZnTPP.