Strain and grain size of TiO2 nanoparticles from TEM, Raman spectroscopy and XRD: The revisiting of the Williamson-Hall plot method

Kibasomba, Pierre M.; Dhlamini, Simon Mokhotjwa; Maaza, M.; Liu, Chuan Pu; Rashad, M.M.; Rayan, D. A.; Mwakikunga, Bonex W.

doi:10.1016/j.rinp.2018.03.008

Cited by 374 publications

(128 citation statements)

References 35 publications

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“…WH‐UDM plot for the synthesized TiO 2 nanoparticles is represented in Figure . 4sin θ was plotted on the x ‐axis while β cos θ was plotted on the y‐axis in this graph . Crystallite size D and strain ε were calculated from linear fit data of plot and mentioned in Table .…”

Section: Resultsmentioning

confidence: 99%

Sol‐gel–mediated synthesis of TiO₂ nanocrystals: Structural, optical, and electrochemical properties

Sharma

Sarkar

Jha

et al. 2019

Int J Applied Ceramic Tech

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Nanoparticles of titanium dioxide were prepared using the sol-gel method without any impurity. Rietveld refinement of XRD data confirmed the anatase phase of synthesized nanoparticles with space group I4 1/ amd (141). XRD pattern revealed the crystalline nature of synthesized nanopowder. The average crystallite size of synthesized nanoparticles was calculated 7.5 nm. The electrochemical performance of synthesized TiO 2 nanopowder was investigated as working electrode. The electrochemical reaction was found diffusion-controlled as observed from cyclic voltammetry (CV) studies at different scan rates. The diffusion-controlled charge storage mechanism also confirmed by charge transfer resistance and Warburg impedance, as calculated from the EIS analysis. SEM micrograph showed the plate-like structure grown in cluster cloud of particles of synthesized TiO 2 nanocrystals. Absorbance and optical bandgap were obtained using UV-Vis spectra. De-convoluted PL spectra provided the emission pattern from the ultra-violet region to green region due to the presence of interstitial oxygen vacancies. The tune bandgap with EIS measurements of synthesized TiO 2 nanoparticles offers its potential application in energy storage devices and photovoltaic applications. K E Y W O R D SAnatase TiO 2 , CV studies, EIS, PL emission, X-ray diffraction

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Section: Resultsmentioning

confidence: 99%

Sol‐gel–mediated synthesis of TiO₂ nanocrystals: Structural, optical, and electrochemical properties

Sharma

Sarkar

Jha

et al. 2019

Int J Applied Ceramic Tech

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“…It is clear from these equations that annealing temperature promotes grain growth in the nanomaterials. This behavior is reflected by the number of nanoparticle systems including ferrites, 48,49 oxides, 50,51 and titanates 52 synthesized using same method.…”

Section: Resultsmentioning

confidence: 99%

Local Electronic Structure Perspectives of Nanoparticle Growth: The Case of MgO

Singh

Chae

2019

ACS Omega

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Herein, we reported nanoparticle growth from the point of view of the local electronic structure by taking MgO as a prototype material. These nanoparticles were obtained from the sol–gel autocombustion process. The precursor formed in this process was annealed for various temperatures ranging from 300 to 1200 °C for 0.5 and 1 h. It was observed that the amorphous phase occurred in the material synthesized at an annealing temperature of 300 °C for 1 h. This phase transformed to crystalline when the annealing temperature was increased to 350 °C. Crystallite size increased with annealing temperature; however, annealing time did not influence the crystallite size. To get deeper insights of modifications occurring at the atomic scale during crystallization growth, the local electronic structure of synthesized materials was investigated by measuring near-edge X-ray absorption fine structure at Mg, O, N, and C K-edges. These results envisaged that Mg 2+ ion coordination improved with the increase of annealing temperature. It was also observed that both annealing time and annealing temperature are sensitive to the local electronic structural changes.

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“…One justification for this is that the speed of sound has been shown to be an accurate predictor for the average phonon frequency across material systems [40]. Additionally, it is known that Raman-active optical modes typically have a linear strain dependence that can also be characterized by a Gruneisen parameter [41,42]. From theoretical considerations, this optical Gruneisen parameter is ≈ 6.5 for ionic materials and ≈ 3 for covalently bonded materials [42].…”

Section: Author Manuscriptmentioning

confidence: 99%

Lattice Softening Significantly Reduces Thermal Conductivity and Leads to High Thermoelectric Efficiency

et al. 2019

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The influence of micro/nanostructure on thermal conductivity is a topic of great scientific interest and of particular technological importance to thermoelectrics. The current understanding is that structural defects primarily decrease thermal conductivity through phonon scattering where the phonon dispersion and speed of sound are fixed when describing thermal transport, especially when chemical composition is unchanged. Experimental work on a PbTe model system is presented which shows that the speed of sound linearly decreases with increased internal-strain. This softening of the materials lattice completely accounts for the reduction in lattice thermal conductivity, without the introduction of additional phonon scattering mechanisms. Additionally, we show that a major contribution to the reduction in thermal conductivity, and the resulting improvement in thermoelectric figure of merit (zT > 2), in high efficiency Na-doped PbTe can be attributed to this internal-strain induced lattice softening effect. While inhomogeneous internal-strain fields are known to introduce phonon scattering centers, this study demonstrates that internal-strain can also soften a materials lattice on average, modifying the speeds of sound and phonon dispersion. This presents new avenues to control lattice thermal conductivity, beyond phonon scattering, with microstructural defects and internal-strain. In practice, many engineering materials will exhibit both softening and scattering effects, as is shown in silicon. This work shines new light on studies of thermal conductivity in fields of energy materials, microelectronics, and nano-scale heat transfer.

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Strain and grain size of TiO2 nanoparticles from TEM, Raman spectroscopy and XRD: The revisiting of the Williamson-Hall plot method

Cited by 374 publications

References 35 publications

Sol‐gel–mediated synthesis of TiO₂ nanocrystals: Structural, optical, and electrochemical properties

Sol‐gel–mediated synthesis of TiO₂ nanocrystals: Structural, optical, and electrochemical properties

Local Electronic Structure Perspectives of Nanoparticle Growth: The Case of MgO

Lattice Softening Significantly Reduces Thermal Conductivity and Leads to High Thermoelectric Efficiency

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Strain and grain size of TiO2 nanoparticles from TEM, Raman spectroscopy and XRD: The revisiting of the Williamson-Hall plot method

Cited by 374 publications

References 35 publications

Sol‐gel–mediated synthesis of TiO2 nanocrystals: Structural, optical, and electrochemical properties

Sol‐gel–mediated synthesis of TiO2 nanocrystals: Structural, optical, and electrochemical properties

Local Electronic Structure Perspectives of Nanoparticle Growth: The Case of MgO

Lattice Softening Significantly Reduces Thermal Conductivity and Leads to High Thermoelectric Efficiency

Contact Info

Product

Resources

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Sol‐gel–mediated synthesis of TiO₂ nanocrystals: Structural, optical, and electrochemical properties

Sol‐gel–mediated synthesis of TiO₂ nanocrystals: Structural, optical, and electrochemical properties