SbSI Nanosensors: from Gel to Single Nanowire Devices

Abstract

The gas-sensing properties of antimony sulfoiodide (SbSI) nanosensors have been tested for humidity and carbon dioxide in nitrogen. The presented low-power SbSI nanosensors have operated at relatively low temperature and have not required heating system for recovery. Functionality of sonochemically prepared SbSI nanosensors made of xerogel as well as single nanowires has been compared. In the latter case, small amount of SbSI nanowires has been aligned in electric field and bonded ultrasonically to Au microelectrodes. The current and photocurrent responses of SbSI nanosensors have been investigated as function of relative humidity. Mechanism of light-induced desorption of H2O from SbSI nanowires’ surface has been discussed. SbSI nanosensors have been tested for concentrations from 51 to 106 ppm of CO2 in N2, exhibiting a low detection limit of 40(31) ppm. The current response sensitivity has shown a tendency to decrease with increasing CO2 concentration. The experimental results have been explained taking into account proton-transfer process and Grotthuss’ chain reaction, as well as electronic theory of adsorption and catalysis on semiconductors.

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“…It was probably due to water adsorption in the form of clusters of H 2 O molecules agglomerated on the nanowire boundaries and near the contacts between nanowires. An electric current response of SbSI nanowires to humidity changes was found to be exponential [33,35]. A similar behavior was observed for ferroelectric potassium niobate (KNbO 3 ) nanofibers by Ganeshkumar et al [59].…”

“…This high sensitivity of SbSI nanowires to humidity changes was explained taking into account dissociation of water molecules on the SbSI surface and generation of mobile protons. As it was proposed elsewhere [33][34][35], the humidity sensing mechanism relies on Grotthuss' chain reaction [55], where proton transfer occurs in hydronium and an ion-conductive layer is formed on the surface of SbSI nanowires.…”

“…It has involved dispersion of SbSI xerogel in toluene, deposition of dispersed solution on special substrate equipped with microelectrodes, electric field-assisted alignment of nanowires, and their bonding to microelectrodes using ultrasonic nanowelding. Such prepared devices have been successfully applied for humidity sensing [35,57], as well as for detection of different gas molecules (H 2 [58], O 2 [58], and N 2 O [56], CO 2 [35]). Comparing properties of humidity sensors made of an array of a few aligned SbSI nanowires and SbSI xerogel, it was concluded in [35] that latter one exhibits longer time response and simultaneously higher sensitivity to humidity changes.…”

“…Such prepared devices have been successfully applied for humidity sensing [35,57], as well as for detection of different gas molecules (H 2 [58], O 2 [58], and N 2 O [56], CO 2 [35]). Comparing properties of humidity sensors made of an array of a few aligned SbSI nanowires and SbSI xerogel, it was concluded in [35] that latter one exhibits longer time response and simultaneously higher sensitivity to humidity changes. It was probably due to water adsorption in the form of clusters of H 2 O molecules agglomerated on the nanowire boundaries and near the contacts between nanowires.…”

“…Zero-and one-dimensional ferroelectric nanomaterials have been fabricated using different processing methods, e.g., vapor-phase (Sb 2 S 3 nanowires [17], SbSI nanorods [18]), hydrothermal (BaTiO 3 nanowires [14,[19][20][21], BaTiO 3 nanoparticles [22], BiFeO 3 [23], KNbO 3 nanorods [24], KNbO 3 nanowires [25]), solvothermal (LiNbO 3 nanocrystals [26]), colloidal (Sb 2 S 3 nanowires [27]), sol-gel (PbTiO 3 nanotubes [28,29]), mechanochemically assisted (Bi 4 Ti 3 O 12 [30]), electrospinning (BiFeO 3 nanofibers [9], poly(vinylidene fluoride) nanofibers [31]), and sonochemical (SbSI nanowires [32][33][34][35]). More information about recent trends in fabrication techniques of 0D and 1D ferroelectric nanomaterials can be found elsewhere [2,36].…”