Large-scale synthesis of single-crystalline self-standing SnSe₂ nanoplate arrays for wearable gas sensors

Abstract

Advances in two-dimensional semiconducting thin films enable the realization of wearable electronic devices in the form factor of flexible substrate/thin films that can be seamlessly adapted in our daily lives. For wearable gas sensing, two-dimensional materials, such as SnSe, are particularly favorable because of their high surface-to-volume ratio and strong adsorption of gas molecules. Chemical vapor deposition and liquid/mechanical exfoliation are the widely applied techniques to obtain SnSe thin films. However, these methods normally result in non-uniform and isolated flakes which cannot apply to the practical industrial-scale wearable electronic devices. Here, we demonstrate large-scale (10 cm × 10 cm), uniform, and self-standing SnSe nanoplate arrays by co-evaporation process on flexible polyimide substrates. Both structural and morphological properties of the resulting SnSe nanoplates are systematically investigated. Particularly, the single-crystalline SnSe nanoplates are achieved. Furthermore, we explore the application of the polyimide/SnSe nanoplate arrays as wearable gas sensors for detecting methane. The wearable gas sensors show high sensitivity, fast response and recovery, and good uniformity. Our approach not only provides an efficient technique to obtain large-area, uniform and high-quality single-crystalline SnSe nanoplates, but also impacts on the future developments of layered metal dichalcogenides-based wearable devices.

Molecular understanding of a π-conjugated polymer/solid-state ionic liquid complex as a highly sensitive and selective gas sensor

“…3,4 Polymer sensors offer highly functionalised groups ideal for VOC sensing with high sensitivity, synthetically tunable selectivity, and room temperature operation, 5 offering a competitive alternative to the inorganic electronics. 6,7 However, poor electrical characteristics and low surface interactions of organic semiconductors arising from a high-degree of structural disorder and inferior dielectric properties, respectively, must be improved to ensure the desirable sensing capabilities of chemiresistors (i.e., selectivity, sensitivity, speed, and stability). 8 Within the context of improving the electrical characteristics of OSCs, ionic liquids have been generally used to modulate the carrier density of conjugated polymers.…”

Flowerlike Tin Diselenide Hexagonal Nanosheets for High-Performance Lithium-Ion Batteries

“…The corresponding Barrett-Joyner-Halenda (BJH) porosity distribution curve is shown Figure 2B, and the calculated specific pore size distribution of F-SnSe 2 is estimated to be 1-10 nm. Raman spectra ( Figure 2B) present two characteristic peaks located at 116 and 185 cm −1 , corresponding to the Eg and A1g mode of SnSe 2 , respectively (Chen M. et al, 2018). The surface chemical states of F-SnSe 2 were further studied by XPS as shown in Figure S2.…”

Recent Progress in Nanomaterial Enabled Chemical Sensors for Wearable Environmental Monitoring Applications

“…[67] Polymeric substrates are the most conventional substrates utilized to fabricate the WCESs due to their flexibility, stretchability, low cost as well as roll to roll producibility. Several polymer films are used in recent WCESs including polyethylene terephthalate (PET), [23,[68][69][70][71][72][73][74][75][76][77][78][79] polyimide (PI), [80][81][82][83][84][85][86] polyurethane (PU), [22,87,88] polyethylene (PE), [89] and acrylate. [90] The choice in polymeric substrates is directly associated with the application-specific constraints in terms of mechanical, electrical, chemical, and thermal requirements.…”

“…Both the solid phase and liquid phase of metals are used for electrodes. Despite being costly, gold (Au) nanostructures have been adopted as electrode material for most of the recent metal electrode-based WCESs [23,79,[84][85][86]122,139,154] due to their excellent biocompatibility and superior resistance to oxidation. Beside Au, several researchers used silver (Ag), [76,106,109,111] copper (Cu), [77,135,155] aluminum (Al), [141,[156][157][158] platinum (Pt), [75,83] and nickel (Ni) [97] nanostructures to fabricate WCES electrodes.…”

“…[162,163] Several WCESs with TMDs as active materials are reported including WSe 2 NS, [70] WS 2 NS, [98] MoSe 2 NS, [85] MoS 2 NS, [107] and SnSe 2 NS. [84] Carbonbased nanostructures with different dimensionality are another attractive option to be used as active material in WCESs. Owing to the outstanding chemical, mechanical and electrical properties, carbon-based nanostructures are widely used by the researchers for environmental parameters detection.…”