Optical Waveguide BTX Gas Sensor Based on Yttrium-Doped Lithium Iron Phosphate Thin Film

Abstract

Yttrium-doped LiFePO 4 powder was synthesized using the hydrothermal method in one step and was used as a sensing material. An optical waveguide (OWG) sensor based on Yttrium-doped LiFePO 4 has been developed by spin coating a thin film of LiFe 0.99 Y 0.01 PO 4 onto a single-mode Tin-diffused glass optical waveguide. Light was coupled into and out of glass OWG employed by a pair of prisms. The guided wave transmits in waveguide layer and passes through the film as an evanescent wave. The sensing film is stable in air, but when exposed to target gas at room temperature, its optical properties such as transmittance (T) and refractive index (n f ) were changed; thus, the transmitted light intensity was changed. The LiFe 0.99 Y 0.01 PO 4 thin film OWG exhibits reversible response to xylene gas in the range of 0.1-1000 ppm. When the concentration of BTX gases was lower than 1ppm, other substances caused a little interference with the detection of xylene vapor. Compared to pure LiFePO 4 thin film OWG, this sensor exhibited higher sensitivity to BTXs.

Preparation and Xylene‐Sensing Properties of Co3O4 Nanofibers

“…Thus, the detection and measurement of xylene are of great significance. Hitherto, various techniques and methods such as gas chromatography technique, optical waveguide technique, optical planar Bragg grating sensors, chemical sensors, biosensors, and magnetoelastic sensors have been employed to detect xylene, among which chemical sensors based on metal oxide semiconductor receive great attention due to their good performance, low cost, portability, convenient fabrication, and operating process, etc …”

Metal Oxide Nanoparticle-Decorated Few Layer Graphene Nanoflake Chemoresistors for the Detection of Aromatic Volatile Organic Compounds

“…Optical based sensors, multisensor arrays, and chemoresistive sensors are among the most studied approaches for the detection of volatile organic compounds (VOCs) in general, as well as benzene, toluene, and xylene (BTX) in particular [ 6 , 7 , 8 ]. They offer suitable alternatives to the classical, expensive, bulky, and time-consuming BT detection techniques like chromatography and mass spectrometry [ 9 ].…”

Optical-Electricity Gas-Sensing Property Detection of SDBS-WO3 Film at Room Temperature

“…20 OWG gas sensors have promising application prospects in detecting toxic gases because they can be operated at room temperature, have a fast temporal response and recovery time, are immune to electromagnetic fields, and are inexpensive. [21][22][23] This paper reports on the development of gas sensors using an OWG slab with a modified film. In this work, we used a WO3 nanoparticle suspension as the sensing material for the preparation of SDBS-WO3 thin film/Sn-doped glass OWG components and the determination of their optical gas sensing properties toward different gases at room temperature.…”

“…The electrochemical gas sensitivity of the SDBS-WO3 film was tested, based on the relationship between the resistance of the metal oxide semiconductor and the refractive index (n ∝ 1/R). 21 We then compared the trend of the variation of resistance and the output light intensity.…”