Humidity‐Initiated Gas Sensors for Volatile Organic Compounds Sensing

Abstract

A new volatile organic compounds (VOCs) sensing concept called humidityinitiated gas (HIG) sensors is described and demonstrated. HIG sensors employ the impedance of water assembled at sensor interfaces when exposed to humidity to sense VOCs at low concentrations. Here, two HIG sensor variants are studied-Type I and Type II. Type I sensors benefit from simplicity, but are less attractive in terms of key performance metrics, including response time and detection limits. Type II sensors are more complex, but are more attractive in terms of key performance metrics. Notably, it is observed that the best-in-class Type II HIG sensors achieve <2 min response times and <10 ppb detection limit for geranyl acetone, a VOC linked to the asymptomatic form of Huanglongbing (HLB) citrus disease. Both Type I and Type II sensors are assembled from off-the-shelf materials and demonstrate remarkable stability at high humidity. HIG sensors are proposed as an attractive alternative to existing VOCs sensors for remote field detection tasks, including VOCs detection to diagnose HLB citrus disease.

Unique Photoactivated Time‐Resolved Response in 2D GeS for Selective Detection of Volatile Organic Compounds

“…The Fermi level moves toward the valance or conduction band, due to adsorption and desorption between VOC molecules and GeS surface. The time-resolved current response of the GeS sensor when exposed to acetone at different concentrations (10,20,50,100,150,200 2c). The sensor response as a function of acetone concentrations from 10 to 300 ppm at room temperature is shown in Figure 2d.…”

Recent Progress of Nanostructured Sensing Materials from 0D to 3D: Overview of Structure–Property‐Application Relationship for Gas Sensors

“…By analyzing and quantizing the volatile organic compounds (VOCs) from exhaled breath, it is possible to realize rapid early medical diagnosis of diseases (e.g., diabetes, asthma, kidney, halitosis, and lung cancer) in a noninvasive and convenient manner. [ 3,4 ] Great potential in other application fields including but not limited to food safety and wearable electronics also holds enormous implications for exploiting practical gas sensors. [ 5–7 ]…”

Functionalized luminescent covalent organic frameworks hybrid material as smart nose for the diagnosis of Huanglongbing

“…[16][17][18] Currently, the widely accepted method for the identification of C. liberibacter is a polymerase chain reaction (PCR)-based assay. 19 However, PCR is an expensive and time-consuming process which is challenging because the C. liberibacter pathogen load is unevenly distributed in plant tissues, and may be present in low titers. 20 Volatile organic compound (VOC) detection is an ideal approach for the early diagnosis of HLB.…”

“…[21][22][23] The three vapors involved are geranylacetone (GA), linalool (Lin) and phenylacetal (PhA). 19 Detecting disease by odor is beneficial for field use. The potential of non-invasive, portable monitoring devices for VOCs has been demonstrated for real-time pest and disease monitoring in agricultural and horticultural settings.…”