Photoelectrochemical Water Splitting on a Delafossite CuGaO<sub>2</sub>Semiconductor Electrode

Lee, Myung Won; Kim, Don; Yoon, Yong Tae; Kim, Yeong Il

doi:10.5012/bkcs.2014.35.11.3261

Cited by 22 publications

(11 citation statements)

References 21 publications

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“…The CuGaO 2 material has shown favorable attributes in terms of its ability to catalyze overall water-splitting of adsorbed H 2 O, meaning that its band edges are likely to be located at suitable energies in order to satisfy the conditions for H 2 O redox potential. However, Lee et al [38] also describe reduced photocatalytic activity below UV wavelengths (hν < 3.2 eV), in spite of the fact that CuGaO 2 having also shown weaker absorption edges around 2.7 eV in separate studies [37].…”

Section: Introductionmentioning

confidence: 98%

Band gap determination in multi-band-gap CuFeO2 delafossite epitaxial thin film by photoconductivity

et al. 2019

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The photoconductivity within a wavelength range of 450-1100 nm was determined for a sample of epitaxial delafossite CuFeO 2 film grown by pulsed laser deposition. The film thickness was estimated to be 75 nm. The resistance of the films was determined with four-contact van der Pauw's method and using monochromatic illumination of the film. The most significant change in resistance resulted in three rapid lineal conductivity increases at photon energies of ~ 1.5 eV (gap-1), ~ 2.1 eV (gap-2) and ~ 2.5 eV (gap-3). The conductivity properties are well correlated with prior optical absorption results obtained in the NIR-VIS region using transmittance spectroscopy.

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Section: Introductionmentioning

confidence: 98%

Band gap determination in multi-band-gap CuFeO2 delafossite epitaxial thin film by photoconductivity

et al. 2019

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“…However, Cu + -based delafossite oxides (CuMO 2 , M = Fe, Co, Cr, Al, etc. ) provide an alternative to solve the stability issue, while maintaining the optoelectronic properties suitable for PEC, making them promising photocathode materials. − Among the delafossite oxides, CuFeO 2 is considered as the most appealing material because of its suitable band gap for visible light absorption, high stability, and earth-abundant elements. − Furthermore, it has been reported that CuFeO 2 shows ferroelectric properties, which may provide a favorable internal electric field for fast separation and transport of photoexcited carriers. Besides, CuFeO 2 has also been demonstrated to reduce CO 2 to formate under illumination, and the conversion efficiency of CuFeO 2 reaches the maximum at −0.9 V saturated calomel electrode .…”

Section: Introductionmentioning

confidence: 99%

Revealing the Electronic Structure and Optical Properties of CuFeO₂ as a p-Type Oxide Semiconductor

Zhang

et al. 2021

ACS Appl. Electron. Mater.

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Delafossite CuFeO2 is a p-type oxide semiconductor with a band gap of ∼1.5 eV, which has attracted great interests for applications in solar energy harvesting and oxide electronics. However, there are still some discrepancies in the literature regarding its fundamental electronic structure and transport properties. In this paper, we use a synergistic combination of resonant photoemission spectroscopy and X-ray absorption spectroscopy to directly study the electronic structure of well-defined CuFeO2 epitaxial thin films. Our detailed study reveals that CuFeO2 has an indirect and d–d forbidden band gap of 1.5 eV. The top of the valence band (VB) of CuFeO2 mainly consists of occupied Fe 3d states hybridized with Cu 3d and O 2p, and the bottom of the conduction band (CB) is primarily made up of unoccupied Fe 3d states. The localized nature of the Fe 3d states at both CB and VB edges would limit the carrier mobility and the dynamics of photoexcited carriers. In addition, Mg doping at Fe sites in CuFeO2 increases the hole carrier concentration and leads to a gradual shift of the Fermi level toward the VB. These insights into its electronic structure are of fundamental importance for rational designing and improving the performance of CuFeO2 as photocatalysts.

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“…Wide‐bandgap delafossite materials have also been examined for PEC water splitting. Besides CuGaO 2 , [ 128 ] Díaz‐García et al [ 129 ] inspected the photoelectrochemical properties of CuCrO 2 delafossite thin films prepared by a sol gel route. Although the material bandgap is too wide to absorb in the visible range (3.15 eV) of the solar spectrum, the IPCE attained values near 6% at 350 nm, which is remarkably high compared with other p‐type oxide materials.…”

Section: Ternary Oxides As Photocathodesmentioning

confidence: 99%

Progress in Ternary Metal Oxides as Photocathodes for Water Splitting Cells: Optimization Strategies

Díez‐García

Gómez

2022

Solar RRL

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The conversion of solar energy into fuels and, specifically hydrogen, is a critical process for ensuring the sustainability of the future energy system. Among the different ways of converting solar energy into fuels and chemicals, photoelectrochemical tandem cells, containing two photoactive materials, stand out as they have the potential for direct solar‐to‐fuel conversion, thus minimizing cost. The implementation of photoelectrolysis for hydrogen generation is hindered by the lack of suitable electrode materials, particularly photocathodes. Among the candidates for photocathodes, ternary (and multinary) transition metal oxides have the advantage of lower cost and, potentially, higher stability than other metal compounds. Herein, the aim is to provide an overview of the current state of the art for ternary oxides (spinels, delafossites, perovskites, etc.), with a focus on the modification strategies that can optimize their behavior and applicability. Both copper‐based and iron‐based ternary oxides are the most studied and, currently, the most promising. Among the strategies being used for their optimization, doping, the deposition of underlayers and overlayers, and the use of cocatalysts are the most popular. However, it is apparent that both solar‐to‐hydrogen efficiencies and stability will need to be addressed in the future. Some guidelines in this respect are also provided.

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Photoelectrochemical Water Splitting on a Delafossite CuGaO₂Semiconductor Electrode

Cited by 22 publications

References 21 publications

Band gap determination in multi-band-gap CuFeO2 delafossite epitaxial thin film by photoconductivity

Band gap determination in multi-band-gap CuFeO2 delafossite epitaxial thin film by photoconductivity

Revealing the Electronic Structure and Optical Properties of CuFeO₂ as a p-Type Oxide Semiconductor

Progress in Ternary Metal Oxides as Photocathodes for Water Splitting Cells: Optimization Strategies

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Photoelectrochemical Water Splitting on a Delafossite CuGaO2Semiconductor Electrode

Cited by 22 publications

References 21 publications

Band gap determination in multi-band-gap CuFeO2 delafossite epitaxial thin film by photoconductivity

Band gap determination in multi-band-gap CuFeO2 delafossite epitaxial thin film by photoconductivity

Revealing the Electronic Structure and Optical Properties of CuFeO2 as a p-Type Oxide Semiconductor

Progress in Ternary Metal Oxides as Photocathodes for Water Splitting Cells: Optimization Strategies

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Photoelectrochemical Water Splitting on a Delafossite CuGaO₂Semiconductor Electrode

Revealing the Electronic Structure and Optical Properties of CuFeO₂ as a p-Type Oxide Semiconductor