2D Sn-doped ZnO ultrathin nanosheet networks for enhanced acetone gas sensing application
Introduction
Metal oxide semiconductor nanomaterials are considered as one of the most important classes of multifunctional materials due to their excellent properties and several potential applications [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13]. Among various metal oxide nanomaterials, the II-VI semiconductor zinc oxide (ZnO) possess a special place because of its remarkable properties and wide applications. The properties of ZnO include its n-type conductivity, wide direct band gap (~3.37 eV), larger free exciton binding energy (60 meV), high chemical/physical stability and unique electrical and optical properties. Moreover, because of the anisotropic crystal growth, ZnO possesses diverse morphologies such as nanotubes [14], [15], nanospheres [16], nanorods [17], nanofibres [18], nanowires [19], nanobelts [20], nanoflower [21], nano-mushroom [22], and so on which can selectively be used for various specific applications. Further, because of the several excellent properties, ZnO is widely used for variety of applications, to name a few, photocatalyst, chemical sensors, biosensors and gas sensors, field emission devices, field effect transistors (FETs), dye-sensitized solar cells, antimicrobial agents, light emitting diodes, nanogenerators, photodiodes, heterojunction diodes, and so on [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13]. Interestingly, ZnO nanomaterials are also efficiently used to fabricate high sensitive gas sensors. ZnO nanomaterials exhibit variation in resistance values when exposed to different reducing and oxidizing gases, thus show potential to be used as gas sensing material. However, due to poor gas response, at lower gas concentrations, and selectivity limit the use of ZnO nanomaterials for gas sensing applications. Thus, for better gas sensing performance, the conductivity, electron concentration and surface reaction kinetics should be optimized for ZnO nanomaterials which could be achieved by the doping, surface modification, coatings, etc. Recently, variety of doped ZnO nanomaterials were used to fabricate various gas sensors. Transition metals (Mn, Fe, Co and Ni) doped ZnO nanomaterials were synthesized and used for gas sensing applications [23]. Authors claimed that the Co-doped ZnO nanomaterial was responsive towards ethanol whereas Mn and Ni doped ZnO materials exhibited better responses for acetone; however Fe-doped ZnO nanomaterials showed no response towards any gas, i.e. CO, ethanol, and acetone gases [23]. Zhang et al. synthesized crystalline hexagonal prism-like Cr-doped ZnO nanorods which exhibited good sensing response towards acetone gas due to the fact that the Cr3+ doping into ZnO resulted in the release of one free electron which increases the adsorbed oxygen species density on the surface and hence significantly contributed in the gas sensing properties [24]. Xu et al. reported the fabrication and characterization of acetone gas sensor based on La-doped ZnO nanofibers which exhibited reasonable response and recovery time for 200 ppm acetone gas at 340 °C [25]. In another report, Rh-doped ZnO materials also showed acetone gas sensitivity along with low response and recovery times at 340 °C [26].
Among various dopants, doping of tin (Sn) into the lattices of ZnO is considered as an effective way to improve the conductive properties of ZnO as the ionic radius of Sn (0.69 Å) is comparable to zinc (0.74 Å) [27], [28], [29]. As a result, Sn doping in ZnO is supposed to influence the response or sensitivity of these materials for various gases. Recently, Zhang et al. [30] reported a high sensing response for 100 ppm of acetone at 300 °C with the response and recovery times of about 24 and 8 s, respectively using 3D Sn doped ZnO flower-like structures, synthesized through cetyltrimethylammonium bromide (CTAB) assisted hydrothermal synthesis. According to Zhang et al. [31], Sn doping increased the roughness and porosity of the ZnO materials for enhanced sensitivity towards ethanol vapor under visible light irradiation at low temperature with the very low response and recovery times of ~1 s and ~5 s, respectively. In another report, Sinha et al. [32] observed better sensitivity of Sn-doped-ZnO nanorods based sensor towards ethanol and acetone compared to pure ZnO-based sensors. It is documented that the crystallinity, structural properties and bandgap of ZnO thin films can also be controlled by optimizing the Sn contents [33], [34]. Thus, it was observed that the high doping contents of Sn increase the grain size and reduce the crystallinity of ZnO which may result in the decrease of sensing performances [34]. Therefore, optimization of Sn contents into the lattices of ZnO is important to obtain better sensing performance.
Herein, we report a simple and facile hydrothermal process to synthesize 2D Sn-doped ZnO ultrathin nanosheet networks to fabricate high-sensitive acetone gas sensor. The synthesized nanosheets were characterized by several techniques and finally used as functional material to develop gas sensor device. The fabricated gas sensor was tested at different temperatures under the exposure of various concentrations of acetone (CH3COCH3) gas. The best sensing performance of Sn-doped ZnO ultrathin nanosheet networks was observed at 320 °C for 200 ppm of acetone gas.
Section snippets
Materials
For the synthesis of 2D Sn-doped ZnO ultrathin nanosheet networks and fabrication of acetone gas sensors, all the chemicals were used as received without any further purification. Zinc chloride (ZnCl2), tin(II) chloride dihydrate (SnCl2·2H2O), hexamethylenetetramine (HMTA), ammonium hydroxide (NH4OH) were purchased from Sigma-Aldrich. Deionized (DI) water was used as a solvent for the synthesis of nanosheets.
Synthesis of 2D Sn-doped ZnO ultrathin nanosheet networks
A simple and facile hydrothermal method was used for the synthesis of 2D Sn-doped ZnO
Morphological, structural, compositional and optical properties of 2D Sn-ZnO ultrathin nanosheet networks
Fig. 1 depicts the typical XRD pattern of synthesized Sn-doped ZnO material which exhibited various well-defined diffraction peaks appearing at 2θ=31.76°, 34.42°, 36.23°, 47.56°, 56.60°, 62.90°, 66.40°, 67.95° and 69.15° corresponding to the lattice planes of ZnO(100), (002), (101, (102), (110), (103), (200), (112), and (201), respectively. The observed diffraction peaks are fully consistent with the XRD pattern of well-crystalline wurtzite hexagonal phase bulk ZnO and well-matched with the
Conclusion
In summary, 2D Sn-doped ZnO ultrathin nanosheet networks with sharp and pointed edges were successfully synthesized hydrothermally and efficiently utilized for the fabrication of acetone gas sensor application. The detailed sensing results exhibit a continuous increase in the voltage response as the concentration of acetone was increased from 10 to 200 ppm. Sensitivities of 5.556, 4.547, 3.905, 3.278, 2.514 and 1.766 were recorded for 200, 150, 100, 50, 20 and 10 ppm, respectively for acetone at
Acknowledgements
This project was funded by the Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, under Grant No. (RG/1/130/37). The authors, therefore, acknowledge with thanks DSR for technical and financial support.
References (43)
- et al.
Hexagonal Cadmium Oxide nanodisks: efficient scaffold for cyanide ion sensing, and photo-catalytic applications
Talanta
(2016)et al.Ultra-high sensitive hydrazine chemical sensor based on low-temperature grown ZnO nanoparticles
Electrochim. Acta
(2012) - et al.
Nanomaterials for biosensing applications: a review
Front. Chem.
(2014)et al.Surfactant functionalized tungsten oxide nanoparticles with enhanced photocatalytic activity
Chem. Eng. J.
(2016) - et al.
Metal oxide nanostructures and their gas sensing properties: a review
Sensors
(2012)et al.Fabrication and characterization of a highly sensitive hydroquinone chemical sensor based on iron-doped ZnO nanorods
Dalton Trans.
(2015) - et al.
Zinc oxide hollow micro spheres and nano rods: synthesis and applications in gas sensor
Mater. Chem. Phys.
(2014)et al.Growth and characterization of α-Fe2O3 nanoparticles for environmental remediation and chemical sensor applications
Sci. Adv. Mater.
(2015) - et al.
Multigate transistors as the future of classical metal–oxide–semiconductor field-effect transistors
Nature
(2011) - et al.
Applications of metal oxide materials in dye sensitized photoelectrosynthesis cells for making solar fuels: let the molecules do the work
J. Mater. Chem. A
(2013) - et al.
Antimicrobial activity of metal oxide nanoparticles against Gram-positive and Gram-negative bacteria: a comparative study
Int. J. Nanomed.
(2012) - et al.
Hybrid organic-inorganic light emitting diodes: effect of the metal oxide
J. Mater. Chem.
(2010)et al.Dodecyl Ethyl Dimethyl Ammonium Bromide capped WO3 nanoparticles: efficient scaffold for chemical sensing and environmental remediation
Dalton Trans.
(2015) - et al.
Composite metal oxide semiconductor based photodiodes for solar panel tracking applications
J. Alloy. Compd.
(2015)et al.Arobust enzymeless glucose sensor based on CuO nanoseeds modified electrode
Dalton Trans.
(2015) - et al.
Preparation of zinc oxide nanospheres by solution plasma process and their optical property, photocatalytic and antibacterial activities
Mater. Lett.
(2012)
Excellent acetone sensor of La-doped ZnO nanofibers with unique bead-like structures
Sens. Actuators B: Chem.
Temperature-dependent electrical properties of Sn-doped ZnO nanowires
Sci. Adv. Mater.
One-pot hydrothermal preparation of SnO2-ZnO nanohybrids for simultaneous electrochemical detection of Catechol and Hydroquinone
Sens. Lett.
High sensitivity ethanol gas sensor based on Sn-doped ZnO under visible light irradiation at low temperature
Mater. Res.
Synthesis of 1D Sn-doped ZnO hierarchical nanorods with enhanced gas sensing characteristics
Ceram. Int.
Structure, microstructure and optical properties of Sn-doped ZnO thin films
J. Alloy. Compd.
Photoluminescence and gas sensing study of nanostructured pure and Sn doped ZnO
Mater. Sci. Eng. C
Ultrasensitive and selective hydrazine sensor development based on Sn/ZnO nanoparticles
RSC Adv.
Aqueous solution synthesis of SnO nanostructures with tuned optical absorption behavior and photoelectrochemical properties through morphological evolution
Nanoscale
Growth and properties of well-crystalline cerium oxide (CeO2) nanoflakes for environmental and sensor applications
J. Colloid Interface Sci.
Controllable synthesis of hierarchical assembled porous ZnO microspheres for acetone gas sensor
Sens. Actuators B Chem.
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2023, Materials Science and Engineering: BCitation Excerpt :The fluctuations in the resistance characteristics of the semiconductor nanomaterials are caused by these electrons (Eq 7, 8 and 9) [31–32]. However, Navale et al. [33] postulated the creation of either hydrogen or water molecules (more advantageous thermodynamically) on the surface of SZn5 ultrathin nanosheet networks coupled with the oxidation of the acetone into acetic acid and subsequently into CO2 (Eq 10 and 11) [34–36]. Gas sensing characteristics of prepared 1-D Sn doped ZnO nanostructures are compared with literature in Table 1.
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Both authors contributed equally in this work.