Effect of particle size and laser power on the Raman spectra of CuAlO<sub>2</sub> delafossite nanoparticles

Yassin, O.A.; Alamri, S.N.; Joraid, A.A.

doi:10.1088/0022-3727/46/23/235301

Cited by 31 publications

(23 citation statements)

References 17 publications

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“…[41][42][43] SEM images of Samples A and B are shown in Fig. These experiments are aimed at evaluating the quality of spectra and dependence on, for example, power rating and illumination, wavelength, incident intensity, particle morphology and exposure to air.…”

Section: Resultsmentioning

confidence: 99%

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Phonon modes of MgB₂: super-lattice structures and spectral response

Alarco

Chou

Talbot

et al. 2014

Phys. Chem. Chem. Phys.

105

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Micrometre-sized MgB2 crystals of varying quality, synthesized at low temperature and autogenous pressure, are compared using a combination of Raman and infra-red (IR) spectroscopy. These data, which include new peak positions in both spectroscopies for high quality MgB2, are interpreted using DFT calculations on phonon behaviour for symmetry-related structures. Raman and IR activity additional to that predicted by point group analyses of the P6/mmm symmetry are detected. These additional peaks, as well as the overall shapes of calculated phonon dispersion (PD) models are explained by assuming a double super-lattice, consistent with a lower symmetry structure for MgB2. A 2× super-lattice in the c-direction allows a simple correlation of the pair breaking energy and the superconducting gap by activation of corresponding acoustic frequencies. A consistent physical interpretation of these spectra is obtained when the position of a phonon anomaly defines a super-lattice modulation in the a-b plane.

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Section: Resultsmentioning

confidence: 99%

“…The difference in morphology between each sample is demonstrable albeit each sample shows a similar X-ray diffraction pattern for MgB 2 . [41][42][43]47 Fig . 3a shows a comparison of the Raman spectra for Sample A acquired with varying laser power and exposed to air during the acquisition of spectra.…”

Section: Resultsmentioning

confidence: 99%

Phonon modes of MgB₂: super-lattice structures and spectral response

Alarco

Chou

Talbot

et al. 2014

Phys. Chem. Chem. Phys.

105

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“…Investigation of structural and vibrational behavior of CuAlO 2 as a function of particle size shows the expansion of lattice parameters and the cell volume with the reduction of particle size. Raman spectra shows large red shifts (∼60 cm −1 ) and line broadening (∼50 cm −1 ) as the particle size becomes of the order of 13 nm [27]. The electrochemical performance of nano CuAlO 2 with an average particle size of ≈20 nm demonstrated 12 times more catalytic activity in the electrolysis of water to the hydrogen evolution reactions and oxygen evolution reactions compared to bulk CuAlO 2 [28].…”

Section: Introductionmentioning

confidence: 99%

Copper Delafossites under High Pressure—A Brief Review of XRD and Raman Spectroscopic Studies

Garg

Rao

2018

Crystals

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Delafossites, with a unique combination of electrical conductivity and optical transparency constitute an important class of materials with their wide range of applications in different fields. In this article, we review the high pressure studies on copper based semiconducting delafossites with special emphasis on their structural and vibrational properties by synchrotron based powder X-ray diffraction and Raman spectroscopic measurements. Though all the investigated compounds undergo pressure induced structural phase transition, the structure of high pressure phase has been reported only for CuFeO 2 . Based on X-ray diffraction data, one of the common features observed in all the studied compounds is the anisotropic compression of cell parameters in ambient rhombohedral structure. Ambient pressure bulk modulus obtained by fitting the pressure volume data lies between 135 to 200 GPa. Two allowed Raman mode frequencies E g and A 1g are observed in all the compounds in ambient phase with splitting of E g mode at the transition except for CuCrO 2 where along with splitting of E g mode, A 1g mode disappears and a strong mode appears which softens with pressure. Observed transition pressure scales exponentially with radii of trivalent cation being lowest for CuLaO 2 and highest for CuAlO 2 . The present review will help materials researchers to have an overview of the subject and reviewed results are relevant for fundamental science as well as possessing potential technological applications in synthesis of new materials with tailored physical properties.

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“…It has been widely acknowledged that in delafossite structure with Γ = A 1 g +E g +3A 2u +3E u , only the first two modes are Raman active. [36,37] The A modes correspond to the vibrational movements in the direction of Cu-O bonds and the E modes represent the vibrations in the perpendicular direction. A previous report on particulate CuAlO 2 [25] shows two sharp peaks at 418 and 767 cm -1 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Luminescence of delafossite-type CuAlO₂ fibers with Eu substitution for Al cations

Liu

Gong

Mellott

et al. 2016

Science and Technology of Advanced Materials

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CuAlO2 has been examined as a potential luminescent material by substituting Eu for Al cations in the delafossite structure. CuAlO2:Eu3+ nanofibers have been prepared via electrospinning for the ease of mitigating synthesis requirements and for future optoelectronics and emerging applications. Single-phase CuAlO2 fibers could be obtained at a temperature of 1100 °C in air. The Eu was successfully doped in the delafossite structure and two strong emission bands at ~405 and 610 nm were observed in the photoluminescence spectra. These bands are due to the intrinsic near-band-edge transition of CuAlO2 and the f-f transition of the Eu3+ activator, respectively. Further electrical characterization indicated that these fibers exhibit semiconducting behavior and the introduction of Eu could act as band-edge modifiers, thus changing the thermal activation energies. In light of this study, CuAlO2:Eu3+ fibers with both strong photoluminescence and p-type conductivity could be produced by tailoring the rare earth doping concentrations.

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Effect of particle size and laser power on the Raman spectra of CuAlO₂ delafossite nanoparticles

Cited by 31 publications

References 17 publications

Phonon modes of MgB₂: super-lattice structures and spectral response

Phonon modes of MgB₂: super-lattice structures and spectral response

Copper Delafossites under High Pressure—A Brief Review of XRD and Raman Spectroscopic Studies

Luminescence of delafossite-type CuAlO₂ fibers with Eu substitution for Al cations

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Effect of particle size and laser power on the Raman spectra of CuAlO2 delafossite nanoparticles

Cited by 31 publications

References 17 publications

Phonon modes of MgB2: super-lattice structures and spectral response

Phonon modes of MgB2: super-lattice structures and spectral response

Copper Delafossites under High Pressure—A Brief Review of XRD and Raman Spectroscopic Studies

Luminescence of delafossite-type CuAlO2 fibers with Eu substitution for Al cations

Contact Info

Product

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Effect of particle size and laser power on the Raman spectra of CuAlO₂ delafossite nanoparticles

Phonon modes of MgB₂: super-lattice structures and spectral response

Phonon modes of MgB₂: super-lattice structures and spectral response

Luminescence of delafossite-type CuAlO₂ fibers with Eu substitution for Al cations