The aim of the study was to prepare SnO2 nanowires via a combination of electrospinning and the sol–gel method from a polyvinylpyrrolidone (PVP)/dimetylformamide (DMF)/ethanol(EtOH)/tin(IV) chloride pentahydrate (SnCl4·5H2O) solution. The morphology, structure and chemical composition of the obtained PVP/SnO2 nanofibers and SnO2 nanowires were examined using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) as well as a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDX). The optical property analysis was performed on the basis of UV–Vis spectra of absorbance as a function of the wavelength, based on which the rated values of band gaps of the fabricated 1D nanostructures were determined. The morphology analysis showed that the obtained amorphous SnO2 nanowires with crystalline protuberances were characterized by a diameter of 50 to 120 nm. Results demonstrated that nanowires with a ratio of 1:1 precursor to polymer in the spinning solution were characterized by the smallest diameter after calcination and the smallest energy gap of 3.3 eV among all investigated samples. The rest of the studied materials were characterized by a larger energy gap (3.8 and 3.9 eV).

No abstract

The aim of this paper was to prepare SnO 2 nanowires using electrospinning and calcination processes from a poly(vinylpyrrolidone), dimethylformamide, ethanol and tin(IV) chloride pentahydrate solution. The composite PVP/SnCl 4 nanofibers obtained via electrospinning method were dried and calcined in a vacuum to remove the polymer matrix at a temperature of 500 °C for 10 h. Three types of nanowires with a polymer to precursor ratios of 2:1, 1:1, 1:3 were produced. The morphology and chemical composition of as-spun PVP/SnCl 4 nanofibers and SnO 2 nanowires obtained after heat treatment were carried out using a scanning electron microscope (SEM) with an energy-dispersive spectrometer (EDX). The Fourier-transform infrared spectroscopy (FTIR) spectra of the prepared nanomaterials were also investigated. To determine the topography of PVP/SnCl 4 nanofibrous mats, an atomic force microscope (AFM) was used. A 100-fold measurement of the nanowire size showed that, depending on the amount of precursor in the spinning solution, nanowires with diameters ranging from 20 to 260 nm were obtained. The optical property analysis was performed on the basis of absorbance spectra recorded over UV-Vis spectral range. The complex refractive index n and complex dielectric permeability ε of obtained tin oxide nanowires were determined as a function of the radiation energy. Depending on the precursor content in spinning solution, the one-dimensional SnO 2 nanostructures were characterised by a refractive index in the range of 1.51-1.56, whereas the dielectric constant ranged from 2.26 to 2.30. The optical properties and the structure of one-dimensional SnO 2 nanomaterials allow to use this type of materials in the construction of novel type photovoltaic cells and electronic devices.

Today, one of the most popular nanomaterials are thin nanofibrous layers, which are used in many fields of industry, eg electronics, optics, filtration and the textile industry. They can be produced by various methods, such as drawing, template synthesis, molecular self-assembly or phase separation method, but the most common method is electrospinning from a solution or melts. Electrospinning is gaining more and more interest due to its versatility, simplicity and economy as well as the possibility of producing fibers from various types of polymeric, ceramic and metalic materials. Nanofibrous layers produced by this method are characterized by high quality and the desired physicochemical properties.

In recent years, many attempts have been made to improve the sensory properties of SnO2, including design of sensors based on one-dimensional nanostructures of this material, such as nanofibers, nanotubes or nanowires. One of the simpler methods of producing one-dimensional tin oxide nanomaterials is to combine the electrospinning method with a sol-gel process. The purpose of this work was to produce SnO2 nanowires using a hybrid electrospinning method combined with a heat treatment process at the temperature of 600 °C and to analyze the morphology and structure of the one-dimensional nanomaterial produced in this way. Analysis of the morphology of composite one-dimensional tin oxide nanostructures showed that smooth, homogeneous and crystalline nanowires were obtained. Full Text: PDF ReferencesN. Dharmaraj, C.H. Kim, K.W. Kim, H.Y. Kim, E.K. Suh, "Spectral studies of SnO2 nanofibres prepared by electrospinning method", Spectrochim. Acta - Part A Mol. Biomol. Spectrosc. 64, (2006) CrossRef N. Gao, H.Y. Li, W. Zhang, Y. Zhang, Y. Zeng, H. Zhixiang, ... & H. Liu, "QCM-based humidity sensor and sensing properties employing colloidal SnO2 nanowires", Sens. Actuators B Chem. 293, (2019), 129-135. CrossRef W. Ge, Y. Chang, V. Natarajan, Z. Feng, J. Zhan, X. Ma, "In2O3-SnO2 hybrid porous nanostructures delivering enhanced formaldehyde sensing performance", J.Alloys and Comp. 746, (2018) CrossRef M. Zhang, Y. Zhen, F. Sun, C. Xu, "Hydrothermally synthesized SnO2-graphene composites for H2 sensing at low operating temperature", Mater. Sci. Eng. B. 209, (2016), 37-44. CrossRef Y. Zhang, X. He, J. Li, Z. Miao, F. Huang, "Fabrication and ethanol-sensing properties of micro gas sensor based on electrospun SnO2 nanofibers", Sens. Actuators B Chem. 132, (2008), 67-73. CrossRef W.Q. Li, S.Y. Ma, J. Luo, Y.Z. Mao, L. Cheng, D.J. Gengzang, X.L. Xu, S H. Yan, "Synthesis of hollow SnO2 nanobelts and their application in acetone sensor", Mater. Lett. 132, (2014), 338-341. CrossRef E. Mudra, I. Shepa, O. Milkovic, Z. Dankova, A. Kovalcikova, A. Annusova, E. Majkova, J. Dusza, "Effect of iron doping on the properties of SnO2 nano/microfibers", Appl. Surf. Sci. 480, (2019), 876-881. CrossRef P. Mohanapriya, H. Segawa, K. Watanabe, K. Watanabe, S. Samitsu, T.S. Natarajan, N.V. Jaya, N. Ohashi, "Enhanced ethanol-gas sensing performance of Ce-doped SnO2 hollow nanofibers prepared by electrospinning", Sens. Actuators B Chem. 188, (2013), 872-878. CrossRef W.Q. Li, S.Y. Ma, Y.F. Li, X.B. Li, C.Y. Wang, X.H. Yang, L. Cheng, Y.Z. Mao, J. Luo, D.J. Gengzang, G.X. Wan, X.L. Xu, "Preparation of Pr-doped SnO2 hollow nanofibers by electrospinning method and their gas sensing properties", J.Alloys and Comp. 605, (2014), 80-88. CrossRef X.H. Xu, S.Y. Ma, X.L. Xu, T. Han, S.T. Pei, Y. Tie, P.F. Cao, W.W. Liu, B.J. Wang, R. Zhang, J.L. Zhang, "Ultra-sensitive glycol sensing performance with rapid-recovery based on heterostructured ZnO-SnO2 hollow nanotube", Mater. Lett, 273, (2020), 127967. CrossRef F. Li, X. Gao, R. Wang, T. Zhang, G. Lu, Sens. "Study on TiO2-SnO2 core-shell heterostructure nanofibers with different work function and its application in gas sensor", Actuators B Chem, 248, (2017), 812-819. CrossRef S. Bai, W. Guo, J. Sun, J. Li, Y. Tian, A. Chen, R. Luo, D. Li, "Synthesis of SnO2–CuO heterojunction using electrospinning and application in detecting of CO", Sens Actuators B Chem, 226, (2016), 96-103. CrossRef H. Du, P.J. Yao, Y. Sun, J. Wang, H. Wang, N. Yu, "Electrospinning Hetero-Nanofibers In2O3/SnO2 of Homotype Heterojunction with High Gas Sensing Activity", Sensors, 17, (2017), 1822. CrossRef X. Wang, H. Fan, P. Ren, "Electrospinning derived hollow SnO2 microtubes with highly photocatalytic property", Catal. Commun. 31, (2013), 37-41. CrossRef L. Cheng, S.Y. Ma, T.T. Wang, X.B. Li, J. Luo, W.Q. Li, Y.Z. Mao, D.J Gengzang, "Synthesis and characterization of SnO2 hollow nanofibers by electrospinning for ethanol sensing properties", Mater. Lett. 131, (2014), 23-26. CrossRef P.H. Phuoc, C.M. Hung, N.V. Toan, N.V. Duy, N.D. Hoa, N.V. Hieu, "One-step fabrication of SnO2 porous nanofiber gas sensors for sub-ppm H2S detection", Sens. Actuators A Phys. 303, (2020), 111722. CrossRef A.E. Deniz, H.A. Vural, B. Ortac, T. Uyar, "Gold nanoparticle/polymer nanofibrous composites by laser ablation and electrospinning", Matter. Lett. 65, (2011), 2941-2943. CrossRef S. Sagadevan, J. Podder, "Investigation on Structural, Surface Morphological and Dielectric Properties of Zn-doped SnO2 Nanoparticles", Mater. Res. 19, (2016), 420-425. CrossRef