Editors’ Choice—Critical Review—A Critical Review of Solid State Gas Sensors

Abstract

Solid state gas sensors are a core enabling technology to a range of measurement applications including industrial, safety, and environmental monitoring. The technology associated with solid-state gas sensors has evolved in recent years with advances in materials, and improvements in processing and miniaturization. In this review, we examine the state-of-the-art of solid state gas sensors with the goal of understanding the core technology and approaches, various sensor design methods to provide targeted functionality, and future prospects in the field. The structure, detection mechanism, and sensing properties of several types of solid state gas sensors will be discussed. In particular, electrochemical cells (solid and liquid), impedance/resistance based sensors (metal oxide, polymer, and carbon based structures), and mechanical sensing structures (resonators, cantilevers, and acoustic wave devices) as well as sensor arrays and supporting technologies, are described. Development areas for this field includes increased control of material properties for improved sensor response and durability, increased integration and miniaturization, and new material systems, including nano-materials and nano-structures, to address shortcomings of existing solid state gas sensors.

A Review of Low-Cost Particulate Matter Sensors from the Developers’ Perspectives

“…Such low-cost nodes rely on solid-state chemical sensors for gaseous air pollution monitoring, a class of electronic devices that has been investigated and developed since the 1960s [28][29][30]; these sensors also use relatively less popular low-cost PM sensors (LCPMS). This review focuses on this latter class of sensors, which represents a new frontier in research and industrial development, with new products being continuously proposed and investigated (briefly summarized in Table 1).…”

Carbon nanotubes: functionalisation and their application in chemical sensors

“…184 This effect is believed to be caused by the charge transfer between gas molecules and the polymer or the polymer lm's swelling. 185 This sensing response has intensively increased motivation to develop high sensitive and selective chemical sensors by tailoring the compounds of different organic polymers with functionalised CNTs.…”

Electron Beam Induced Tailoring of Electrical Characteristics of Organic Semiconductor Films

“…Wong et al have reviewed the sensing behavior of different CPs as chemiresistive gas sensors and also explained the targeted characteristics that makes the particular CP appropriate for selected gas [198]. Hunter et al have gone over the solid state gas sensors and indicated the oxidation (or doping) plays a crucial role for CP based chemiresistive gas sensors [199]. In addition to doping (or oxidation-reduction), which modifies charge carrier density, other processes can also substantially tailor the electrical conductivity of CPs and lead to alteration in chemiresistive gas sensing.…”