Evaluation of oxygen vacancy in ZnO using Raman spectroscopy

Fukushima, Hiroaki; Kozu, Tomomi; Shima, Hiromi; Funakubo, Hiroshi; Uchida, Hiroshi; Katoda, Takashi; Nishida, Ken

doi:10.1109/isaf.2015.7172660

Cited by 22 publications

(13 citation statements)

References 18 publications

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“…TiO2 [61], and ZnO [62]. In our case, considering only previous XRD results, it is not possible to distinguish between the different causes responsible for such a shift.…”

Section: Figurementioning

confidence: 82%

High photocatalytic activity of aerogel tetragonal and monoclinic ZrO2 samples

Sakfali

Chaabene

Akkari

et al. 2022

Journal of Photochemistry and Photobiology A: Chemistry

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“…TiO2 [61], and ZnO [62]. In our case, considering only previous XRD results, it is not possible to distinguish between the different causes responsible for such a shift.…”

Section: Figurementioning

confidence: 82%

High photocatalytic activity of aerogel tetragonal and monoclinic ZrO2 samples

Sakfali

Chaabene

Akkari

et al. 2022

Journal of Photochemistry and Photobiology A: Chemistry

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“…In H 2 , the proton conductivity of 5LZO-5SDC achieve values of 0.0055–0.028 S cm −1 at 450–550 °C, showing two order of magnitude enhancement as compared to the result in air. This means the composite tends to be more highly ion-conducting in fuel cell operating atmosphere, as former studied has pointed out that ZnO owns few oxygen vacancies in air, but it can gain significantly enriched surface oxygen vacancies after treated in reducing atmosphere [ 47 ].…”

Section: Resultsmentioning

confidence: 99%

Remarkable Ionic Conductivity in a LZO-SDC Composite for Low-Temperature Solid Oxide Fuel Cells

Tian

et al. 2021

Nanomaterials

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Recently, appreciable ionic conduction has been frequently observed in multifunctional semiconductors, pointing out an unconventional way to develop electrolytes for solid oxide fuel cells (SOFCs). Among them, ZnO and Li-doped ZnO (LZO) have shown great potential. In this study, to further improve the electrolyte capability of LZO, a typical ionic conductor Sm0.2Ce0.8O1.9 (SDC) is introduced to form semiconductor-ionic composites with LZO. The designed LZO-SDC composites with various mass ratios are successfully demonstrated in SOFCs at low operating temperatures, exhibiting a peak power density of 713 mW cm−2 and high open circuit voltages (OCVs) of 1.04 V at 550 °C by the best-performing sample 5LZO-5SDC, which is superior to that of simplex LZO electrolyte SOFC. Our electrochemical and electrical analysis reveals that the composite samples have attained enhanced ionic conduction as compared to pure LZO and SDC, reaching a remarkable ionic conductivity of 0.16 S cm−1 at 550 °C, and shows hybrid H+/O2− conducting capability with predominant H+ conduction. Further investigation in terms of interface inspection manifests that oxygen vacancies are enriched at the hetero-interface between LZO and SDC, which gives rise to the high ionic conductivity of 5LZO-5SDC. Our study thus suggests the tremendous potentials of semiconductor ionic materials and indicates an effective way to develop fast ionic transport in electrolytes for low-temperature SOFCs.

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“…ZnO powders were reduced at 400°C for a predetermined time between 30 and 90 min since we have previously reported that Zn vacancies are likely generated in ZnO powders reduced at 600°C for 30 min. 36) Micro-Raman spectroscopy was performed in the spectral range from 50 to 500 cm ¹1 using a micro-Raman system (Photon Design NFR-800-NSD) and a wavenumber resolution of about 0.25 cm…”

Section: Methodsmentioning

confidence: 99%

Evaluation of oxygen vacancies in ZnO single crystals and powders by micro-Raman spectroscopy

Fukushima

Uchida

Funakubo

et al. 2017

J. Ceram. Soc. Japan

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Investigations of defects are important to understand the properties of zinc oxide (ZnO), especially oxygen vacancies, which are intrinsic defects that are easily generated during crystal growth or device processing. In this study, we evaluate the oxygen vacancies in ZnO single crystals and powders using micro-Raman spectroscopy. Reducing ZnO in a hydrogen atmosphere at 400 600°C for 30240 min changes the amount of oxygen vacancies. Raman spectroscopy reveals a slight shift and a decrease in the E 2 (high) phonon mode, which is related to the oxide ion vibration. The peak position of the E 2 (high) mode shifts toward a lower frequency and the peak intensity decreases as the oxygen vacancies increase. This behavior can be explained by the existence of oxygen vacancies in ZnO. Because the E 2 (high) peak shift and the intensity are scaled in accordance with the amount of oxygen vacancies, these correlations offer a simple and useful probe to evaluate oxygen vacancies in ZnO.

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Evaluation of oxygen vacancy in ZnO using Raman spectroscopy

Cited by 22 publications

References 18 publications

High photocatalytic activity of aerogel tetragonal and monoclinic ZrO2 samples

High photocatalytic activity of aerogel tetragonal and monoclinic ZrO2 samples

Remarkable Ionic Conductivity in a LZO-SDC Composite for Low-Temperature Solid Oxide Fuel Cells

Evaluation of oxygen vacancies in ZnO single crystals and powders by micro-Raman spectroscopy

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