Structural and optical properties of ZnO nanoparticles synthesized at different pH values

Chand, Prakash; Gaur, Anurag; Kumar, Ashavani

doi:10.1016/j.jallcom.2012.05.104

Cited by 73 publications

(28 citation statements)

References 47 publications

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“…As noted above, we collected a large number of published Tauc analyses of undoped ZnO that included plots of the absorbance data against the photon energy . This was critical, as our assessment of the application of the Tauc method required the consistent application of a fitting method, as described below.…”

Section: Modelmentioning

confidence: 99%

Evaluation of the Tauc method for optical absorption edge determination: ZnO thin films as a model system

Viezbicke

Patel

Davis

et al. 2015

Phys. Status Solidi B

895

419

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One of the most frequently used methods for characterizing thin films is UV–Vis absorption. The near‐edge region can be fitted to a simple expression in which the intercept gives the band‐gap and the fitting exponent identifies the electronic transition as direct or indirect (see Tauc et al., Phys. Status Solidi 15, 627 (1966); these are often called “Tauc” plots). While the technique is powerful and simple, the accuracy of the fitted band‐gap result is seldom stated or known. We tackle this question by refitting a large number of Tauc plots from the literature and look for trends. Nominally pure zinc oxide (ZnO) was chosen as a material with limited intrinsic deviation from stoichiometry and which has been widely studied. Our examination of the band gap values and their distribution leads to a discussion of some experimental factors that can bias the data and lead to either smaller or larger apparent values than would be expected. Finally, an easily evaluated figure‐of‐merit is defined that may help guide more accurate Tauc fitting. For samples with relatively sharper Tauc plot shapes, the population yields Eg(ZnO) as 3.276 ± 0.033 eV, in good agreement with data for single crystalline material.

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Section: Modelmentioning

confidence: 99%

Evaluation of the Tauc method for optical absorption edge determination: ZnO thin films as a model system

Viezbicke

Patel

Davis

et al. 2015

Phys. Status Solidi B

895

419

View full text Add to dashboard Cite

show abstract

“…Polar optical phonons in wurtzite nanocrystals of ZnO the frequency of 1LO phonon mode should be in between 574 and 591 cm -1 . So the peak 581.005 cm -1 and 583 cm -1 is attributed to the superimposition of A 1L and E 1L [25]. In addition, it can be seen that, the position of A 1L and E 1L peak shift towards higher wavenumber in case of ZnO nanorods (Fig.…”

Section: Raman Spectroscopic Analysismentioning

confidence: 78%

“…Wurtzite type zinc oxide belongs to space group with two formula units in the primitive cell. The optical phonons at Γ point of the Brillouin zone belongs to the following representation: Γ opt = 1A 1 + 2B 1 + 2E 1 + 2E 2 [25,26]. B 1 modes are Raman silent modes belong to the optical modes, both A 1 and E 1 modes are polar and are split into transverse optical and longitudinal optical (LO) phonons, belongs to the long range electrostatic forces.…”

Section: Raman Spectroscopic Analysismentioning

confidence: 99%

Optical investigation of various morphologies of ZnO nanostructures prepared by PVP-assisted wet chemical method

Parra

Haque

2015

Opt. Spectrosc.

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Various morphologies of zinc oxide have been successfully synthesized via simple poly-vinylpyrrolidone (PVP) assisted wet chemical method. Herein, a comparative study between three different morphologies of ZnO, namely nanoparticles (NP's), nanowalls (NW's) and nanorods (NR's) has been presented. The structural and spectroscopic results reveal that the addition of PVP as capping agent greatly influences the structural and optical behavior of ZnO. X-ray diffraction (XRD) results confirmed pure phase ZnO nanostructures with well crystallinity. It was observed from results that increasing concentration of poly-vinylpyrrolidone from half to equimolar ratio lattice imperfections decrease. ZnO nanorods have biggest crystallite size compared with nanowalls and nanoparticles, confirmed through X-ray diffraction study. The formation of three different morphologies was observed through scanning electron microscopy (SEM). The FTIR and Raman spectroscopic results reveal significant shifts for these ZnO nanostructures in the typical modes assigned to Zn-O, which intercorrelated with the XRD results. The optical band gap energies were found to be decreased from ~3.22 eV for ZnO nanoparticles to 3.14 eV for ZnO nanorods. It was investigated from photoluminescence study that PVP capped ZnO nanostructures have reduced surface trap states and therefore the UV emission and visible emission regions overlap to form a single band. The physical properties and optical behavior realized that, as prepared samples might be applied in energy storage devices and solar cells.

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“…2. The shifting of diffraction peaks indicates the increase in lattice parameters [7]. From XRD data, the crystalline grain size of ZnO NPs at different AA/Zn ratio was calculated by Debye-Scherrer equation, as given below;…”

Section: Methodsmentioning

confidence: 99%

Effect of ascorbic acid on structural properties of ZnO nanoparticles prepared by precipitation process

Chaithanatkun

Chantarawong

Songkeaw

et al. 2015

10th IEEE International Conference on Nano/Micro Engineered and Molecular Systems

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In this work, zinc oxide nanoparticles (ZnO NPs) was prepared by chemical precipitation process. To study the influence of the ascorbic acid on properties of ZnO nanoparticles, the ascorbic acid was added to precursor solution at different molar ratio of ascorbic acid (AA) and zinc during the synthesis process. The characterizations of ZnO nanoparticles were performed using X-ray diffraction (XRD), Raman spectroscope, and field emission scanning electron microscopy (FE-SEM). The effect of ascorbic acid on the structural properties of ZnO NPs was investigated.

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Structural and optical properties of ZnO nanoparticles synthesized at different pH values

Cited by 73 publications

References 47 publications

Evaluation of the Tauc method for optical absorption edge determination: ZnO thin films as a model system

Evaluation of the Tauc method for optical absorption edge determination: ZnO thin films as a model system

Optical investigation of various morphologies of ZnO nanostructures prepared by PVP-assisted wet chemical method

Effect of ascorbic acid on structural properties of ZnO nanoparticles prepared by precipitation process

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