Crystal Structure, Lattice Strain, Morphology, and Electrical Properties of SnO2 Nanoparticles Induced by Low Calcination Temperature

Panya Khaenamkaew,Worasit Palakawong Na Ayuthaya,Dhonluck Manop,Chaileok Tanghengjaroen

doi:10.1155/2020/3852421

Panya Khaenamkaew, Worasit Palakawong Na Ayuthaya + Show 2 more

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https://doi.org/10.1155/2020/3852421

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Abstract

The electrical properties of tin dioxide (SnO2) nanoparticles induced by low calcination temperature were systematically investigated for gas sensing applications. The precipitation method was used to prepare SnO2 powders, while the sol-gel method was adopted to prepare SnO2 thin films at different calcination temperatures. The characterization was done by X-ray diffraction, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The samples were perfectly matched with the rutile tetragonal structure. The average crystallite sizes of SnO2 powders were 45 ± 2, 50 ± 2, 62 ± 2, and 65 ± 2 nm at calcination temperatures of 300, 350, 400, and 450°C, respectively. SEM images and AFM topographies showed an increase in particle size and roughness with the rise in calcination temperature. The dielectric constant decreased with the increase in the frequency of the applied signals but increased on increasing calcination temperature. By using the UV-Vis spectrum, the direct energy bandgaps of SnO2 thin films were found as 4.85, 4.80, 4.75, and 4.10 eV for 300, 350, 400, and 450°C, respectively. Low calcination temperature as 300°C allows smaller crystallite sizes and lower dielectric constants but increases the surface roughness of SnO2, while lattice strain remains independent. Thus, low calcination temperatures of SnO2 are promising for electronic devices like gas sensors.

Highlights

Tin dioxide (SnO2) powders and thin films are essential for several applications such as a transparent electrode in panels [1], materials for rechargeable lithium batteries [2], solar cells [3], and gas sensing materials [4]
We have examined various characteristics of SnO2 thin films and powders by varying temperature. e crystallite structure, that is, particle size, lattice parameter and lattice strain, morphology, topography and roughness, optical properties, and dielectric property, was explored for achieving a suitable condition to obtain various morphologies of SnO2 nanoparticle for the application of devices in sensors
XRD analysis revealed a tetragonal rutile structure with P42/mnm (136) phase group from the synthesized compounds. e average crystalline size increases from 45 ± 2, 50 ± 2, 62 ± 2 to 65 ± 2 nm due to the increase in calcination temperature from 300, 350, 400, to 450°C, respectively. ese results show the persistence of lattice strain, which is independent of calcination temperature

Summary

Introduction

Tin dioxide (SnO2) powders and thin films are essential for several applications such as a transparent electrode in panels [1], materials for rechargeable lithium batteries [2], solar cells [3], and gas sensing materials [4]. As mentioned in the previous paragraph, the efficiency of the SnO2 sensor is firmly controlled by the crystal structure and particle sizes of SnO2. E precipitation method is a promising technique for controlling SnO2 crystal structure and particle size because it produces high purity powder, nanoparticle size, and easy composition control and is of low cost [3,4,5, 15]. Only a few studies have examined crystal structure at low calcination temperature, morphology, and electrical properties in SnO2 powder. Naseem et al [18] first reported the lattice strain of SnO2 powder, which can vary due to the solvents used in the synthesis process. Sufficient research is required to strengthen the above statement. e main challenge is how to use the nano-SnO2 powder and thin films as a gas sensor in industrial uses

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