1D Metal Oxide Semiconductor Materials for Chemiresistive Gas Sensors: A Review

Abstract

While numerous types of gas sensors have been developed for various industries and applications such as the automotive industry, environmental monitoring, and personal safety, nanoscale chemiresistive gas sensors have gained significant research interest due to several advantages such as high sensitivity, low power consumption, and portability. An essential component of these gas sensors is the sensing material where metal oxide semiconductor (MOS) materials are the most prevalent sensing material. Since the adoption of nanoscale synthesis methods for sensing materials development, such as electrospinning and hydrothermal synthesis, many novel 1D MOS‐based nanostructured sensing materials have been demonstrated to enhance gas sensing performance. Overall, nanoengineering approaches and mechanisms for enhancement of gas sensing performance of 1D metal oxide‐based sensing materials are systematically discussed and categorized into several overarching strategies, such as tuning of materials dimension, morphology, and composition. Furthermore, integration of 1D sensing nanomaterials into sensor devices are discussed from the perspective of different chemiresistive sensor architectures and device fabrication methods. Finally, this review also discusses use of 1D MOS materials for emerging and novel electronic nose applications.

One-Dimensional Metal Oxide Nanostructures for Chemical Sensors

“…The functionalization or modification of 1D MOS nanostructures with second-phase materials may be of the decorative-type, only at surface level, when incorporating low amounts of the additives at the surface. It can also involve single mixtures, when mixing 1D nanostructures and the additives randomly, or doping, when additive atoms incorporate in the intrinsic material structure [25,112]. Generally, the methods to functionalize or modify 1D MOS nanostructures fall into two categories: one-step processes in which the additive materials are incorporated simultaneously during the 1D nanostructure formation or multiple-step processes in which the additives are incorporated over the pre-synthetized 1D MOS nanostructures [113].…”

“…Furthermore, novel synthesis techniques allow fine-tuning of the composition, morphology, and structure of the nanomaterials' surface, which, together with possible alterations in the electronic and chemical properties at the nanoscale, could contribute to enhancing the chemical affinity of the MOS nanostructures for specific species [23,24]. Recently one-dimensional (1D) MOS nanostructures have gained increased attention for chemical sensing because they are more applicable to nanoelectronics and nanodevices due to their high-surface-area-to-volume ratio 1D morphology [25,26]; this means that a significant fraction of the atoms is surface atoms that participate actively in surface reactions. In 1D nanostructures the width and thickness are confined to the nanoscale, while the length spans from the micrometric to the millimetric range, allowing 1D nanostructures to contact the microscopic and macroscopic world for many physical measurements.…”

High-temperature NO sensing performance of WO3 deposited by spray coating

“…6 Among the gas detection systems, chemoresistive gas sensors based on semiconductor metal oxides are good candidates due to their several advantages such as simple working principles, greater robustness, relatively low cost, high material sensitivity and real time measurement. 7,8 However, the optimum sensing temperatures obtained from most of the simple metal oxide (NiO, In 2 O 3 , Cr 2 O 3 , Co 3 O 4 , SnO 2 , etc.) are below 400 C. 9,10 A literature survey reveals that, Ga 2 O 3 and TiO 2 are the mostly applied simple metal oxides for high temperature gas sensing.…”

Design and Applications of Liquid Crystal Biophotonic Sensors for Ion Detection

“…The detection principle of the LC sensors is typically based on the competitive binding of an LC and a targeted analyte to a common molecular receptor, [28] which results in the reorientation of the LC molecules and the variation of the optical images. [29][30][31] Compared with traditional sensing techniques such as the metal-oxide-semiconductor sensors, [32] light-addressable potentiometric sensors, [33] and electrochemical sensors, [34] the LC sensors hold the advantages of portability and low cost and show visualized output signals that can be directly observed by the naked eyes using some optical techniques. [35,36] Up to now, a variety of LC sensors have been designed and fabricated, such as the largebirefringence nematic LCs (NLCs) for cancer biomarker detection, [37] the label-free LC biosensor for cecropin B detection, [38] and the LC fiber temperature sensor with high sensitivity.…”