Suspended Graphene/PEDOT: PSS‐PEO Channel for H₂ Gas Sensing Fabricated Using Direct‐Write Functional Fibers

Abstract

and calibrate the sensors before detecting target gases. Second, a gas sensor's performance also depends on the system optimization, such as signal chain design, power consumption, etc., and sensor's operating conditions, such as temperature, humidity, pressure, test chamber design, etc. Finally, all sensors age, drift in performance, and ultimately fail at the end of their life. The cost of operation can be significantly decreased by effectively predicting the sensor's life and reducing unnecessary sensor replacements. In this research work, we fabricate a simple, low-cost, low-power consuming, and robust gas sensor that can detect Hydrogen (H 2 ) gas at a very low concentrations with enhanced sensitivity.Hydrogen (H 2 ) gas is a promising clean and green energy source. H 2 gas, with properties such as high energy density, renewability, and eco-friendly nature, is rising as a potential candidate to replace conventional fossil fuels in the automotive and industrial applications field. [1][2][3] Nevertheless, the low combustion energy (0.02 meJ) and wide flammable range (4-75%) of H 2 gas raise safety concerns and warrant an easy, quick, and reliable leakage detection method. [4,5] Typical commercial H 2 gas sensors employ metal oxide materials, such as SnO 2 , ZnO, and TiO 2 , due to their higher sensitivity toward detecting H 2 . [6][7][8] However, these sensors suffer from high operating temperatures (typically 200-500 °C) and usually have low selectivity. Other than conventional materials, conductive polymers have been studied as alternative sensing materials in chemical sensing to leverage simple processing, chemical versatility, and wide availability. [9] Poly(3,4-ethylene dioxythiophene) doped with polystyrene sulfonate (PEDOT: PSS) is the most commonly used conductive polymer which has attracted significant interest due to its high electrical conductivity, high stability, and ease in the processing. [10] The electrical property of PEDOT: PSS can be tailored via redox reactions and charge transfer due to doping. [11][12][13][14] PEDOT: PSS doped with nanocarbon materials is expected to achieve enhanced sensing properties owing to their high surface-to-volume ratio. Graphene (Gr), among various nanocarbon materials, is the most widely used because of its exceptional physical, chemical, mechanical, and electrical properties. [15][16][17][18] Although pristine graphene has proved low sensitivity toward detecting H 2 molecules, [15,19] chemically modified graphene/PEDOT: PSS nanocomposite films have demonstrated enhanced sensing response with a much shorter response and recovery time. [20] When suspended as a nanoscale bridge, In this study, the hydrogen gas (H 2 ) sensing mechanism of suspended graphene (Gr)/ Poly(3,4-ethylene dioxythiophene): Poly(styrene sulfonate) -Polyethylene oxide (PEDOT: PSS-PEO) composite nanoscale channels precisely patterned with near-field electrospinning is investigated. Suspended Gr/PEDOT: PSS-PEO nanoscale channels not only have a higher surface-to-volume ratio for easy diffusion...

Effect of pH Value on the Electrical Properties of PEDOT:PSS-Based Fiber Mats

“…PSS disperses and stabilizes PEDOT by forming colloidal particles containing a higher number of PSS chains at the periphery and a higher number of PEDOT chains at the core . Due to its electrical properties, PEDOT:PSS-based electrospun fibers have been used in various applications, including gas sensors that detect organic vapors, carbon monoxide, ammonia, and hydrogen gas, as well as strain , and humidity sensors; and thermoelectric devices. − In most of these studies, PEDOT:PSS was blended with a non-conducting carrier polymer, such as poly­(vinyl alcohol) (PVA), − polyvinylpyrrolidone (PVP), or poly­(ethylene oxide) (PEO) , to improve the electrospinnability. In one study by Huang et al, the carrier polymer was avoided by blending PEDOT:PSS with a small amount of magnesium nitrate that acted as a thickener to facilitate electrospinning.…”