Raman study of structural disorder in ZnO nanopowders

Šćepanović, M.; Grujić‐Brojčin, M.; Vojisavljević, Katarina; Bernik, Slavko; Srećković, Tatjana

doi:10.1002/jrs.2546

Cited by 373 publications

(202 citation statements)

References 41 publications

(131 reference statements)

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“…ZnO and the Li-doped ZnO materials presented identical Raman modes and relative intensities (Figure 1 e). The Raman spectra were consistent with that of standard wurtzite ZnO; [28,29] in detail, Raman modes A-D originated from second-order E 2 -low, second-order A 1 -TO, firstorder A 1 -TO, and first-order E 2 -high wurtzite ZnO, respectively. [28] Importantly, Li 2 O typically exhibits a Raman mode at about 523 cm À1 (F 2g mode), [30,31] which was absent from the Raman spectra of Li-doped ZnO, thus further substantiating the successful doping of Li in the ZnO lattice.…”

Section: Resultssupporting

confidence: 71%

Photocatalytic Activity and Selectivity of ZnO Materials in the Decomposition of Organic Compounds

Lin¹,

Cojocaru²,

Chou³

et al. 2013

ChemCatChem

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ZnO and Li‐doped ZnO photocatalysts were prepared by using a solvothermal method, aided by a supercritical drying technique. The structure and morphology of the photocatalysts were investigated by using SEM, X‐ray diffraction (XRD), UV/Vis and Raman spectroscopy. The photocatalytic activity and selectivity were investigated in the aqueous‐phase photodegradation of methylene blue and phenol as model reactions. Herein, it is reported for the first time that Li doping can lead to significant deactivation of the photocatalytic activity (i.e., decreased oxidization capability) of ZnO materials. The distribution of intermediate products (i.e., selectivity) was also significantly modified in the decomposition of phenol catalyzed by Li‐doped ZnO compared to that catalyzed by ZnO. Photoluminescence (PL) and soft X‐ray absorption spectroscopy (XAS) studies suggested that dopant‐induced surface‐defect states acted as electron–hole combination centers and changed the adsorbate/surface binding, thus causing the deactivation of photocatalytic activity and altering the photocatalytic selectivity in Li‐doped ZnO materials.

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Section: Resultssupporting

confidence: 71%

Photocatalytic Activity and Selectivity of ZnO Materials in the Decomposition of Organic Compounds

Lin¹,

Cojocaru²,

Chou³

et al. 2013

ChemCatChem

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“…The first four peaks at 328, 379, 413, and 437 cm -1 are attributed to the E 2H -E 2L , A 1 (TO), E 1 (TO), E 2 (high) modes, respectively [23,24]. It can be observed that the E 2 (high) mode has the strongest intensity for both samples, which confirms that the synthesized samples have a good crystal quality of hexagonal wurtzite phase [22,23]. The E 1 (TO) and A 1 (TO) reflect the strength of the polar lattice bonds [24].…”

Section: Micro-raman Scatteringsupporting

confidence: 70%

The morphology and optical properties of ZnO crystals fabricated by hydrothermal method under pulsed magnetic field

Zhong

et al. 2013

Phys. Status Solidi C

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In this study, ZnO crystals have been synthesized via hydrothermal method by adjusting the component of the precursor with the pulsed magnetic field. The effects of the molar ratio of the reactants and pulsed magnetic field applied in the synthesis process on the microstructure and optical properties of ZnO crystals were investigated systematically. The samples were characterized by X‐ray diffraction, scanning electron microscopy, UV‐Vis spectrophotometer and micro‐Raman scattering. The results demonstrate that pulsed magnetic field increases the defects concentration and reduces the band gap of ZnO. And it also promotes nucleation and crystal growth, the crystals obtained under pulsed magnetic field are more uniform and complete. The change of molar ratios influences the pH value so that the environment for the growth of ZnO crystals changed dramatically. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Zone center optical phonons predicted by group theory are A 1 +2E 2 +E 1 , where A 1 and E 1 modes are polar and split into the transverse optical (TO) and longitudinal optical (LO) phonons. In addition, the E 2 mode consists of two modes: E 2 high which is associated with the vibration of oxygen atoms, and E 2 low which is associated with the Zn sublattice [21][22][23] . The effect of annealing temperature evolution shows that the major difference between the Raman spectra of samples annealed at 500 ºC and 700 ºC is the appearance of E 2 high mode at 438 cm -1 .…”

Section: Resultsmentioning

confidence: 99%

Annealing Effects on the Structural and Optical Properties of ZnO Nanostructures

et al. 2018

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ZnO nanostructures were synthesized by a proteic sol-gel method, using zinc nitrate hexahydrate and gelatin as precursors. Size and shape evolution of ZnO nanostructures were achieved by annealing temperature in the range 250-1000 ºC. The crystalline structure, morphology and optical properties of the ZnO nanoparticles were characterized by X-Ray Diffraction (XRD), Raman Spectroscopy (RS), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and room temperature Photoluminescence (PL). The result of structural characterization shows the formation of platelets and nanorods in the micro-scale and ZnO nanostructures with high quality hexagonal wurtzite crystal. Sharp peaks in RS after annealing temperature, related to wurtzite structure, were observed corroborating with XRD and TEM measurements. Room temperature PL spectra showed two contribution bands which peaked at ~380 nm, originating from the recombination of free excitons, and ~520 nm corresponding to the impurities and structural defects, like oxygen vacancies and zinc interstitial. The effects of annealing temperature in the structural and optical properties are detailed and the results compared among the experimental techniques. The high quality of the samples obtained by an alternative organic precursor method opens a low-cost route to technological applications of zinc oxide.

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Raman study of structural disorder in ZnO nanopowders

Cited by 373 publications

References 41 publications

Photocatalytic Activity and Selectivity of ZnO Materials in the Decomposition of Organic Compounds

Photocatalytic Activity and Selectivity of ZnO Materials in the Decomposition of Organic Compounds

The morphology and optical properties of ZnO crystals fabricated by hydrothermal method under pulsed magnetic field

Annealing Effects on the Structural and Optical Properties of ZnO Nanostructures

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