Positive onset potential and stability of Cu2O-based photocathodes in water splitting by atomic layer deposition of a Ga2O3buffer layer

Li, Changli; Hisatomi, Takashi; Watanabe, Osamu; Nakabayashi, Mamiko; Shibata, Naoya; Domen, Kazunari; Delaunay, Jean‐Jacques

doi:10.1039/c5ee00250h

Cited by 209 publications

(171 citation statements)

References 39 publications

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“…Indeed, Domen and co-workers reported recently an improved onset of photocurrent by judiciously replacing the Al:ZnO layer by Ga2O3 which displays a lower CB band offset with the Cu2O. 84 As shown in Figure 7b,c the ALD-deposited layers not only ameliorate the photocurrent response but also increase the lifetime from a few seconds to hours. 82 Similarly, Lee et al reported the improved stability of p-InP nanopillar photocathodes in acidic media upon coating with a layer (3-5 nm) of TiO2.…”

Section: Semiconductor Coatingmentioning

confidence: 94%

Surface modification of semiconductor photoelectrodes

Guijarro

Prévot

Sivula

2015

Phys. Chem. Chem. Phys.

144

123

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Photoelectrochemical (PEC) cells have emerged as promising devices that afford the direct conversion of solar energy into electric power and/or chemical fuels. Apart from the obvious importance of the bulk properties of semiconductor materials employed as photoelectrodes, the semiconductor-liquid interface has proven to strongly govern surface-related processes, i.e. the stability, charge separation/recombination and catalytic activity. Because of this, numerous surface treatments have been reported in an effort to tailor the physicochemical properties of the semiconductor-liquid interface, and in turn, the overall PEC response. In this Perspective article we provide a brief conceptual overview of these surface engineering treatments, connecting the particular effects on the interfacial energetics with the respective consequences on the performance. The beneficial effects that arise from surface treatment are categorized as (i) the protection of the surface against photocorrosion, (ii) the passivation of deleterious surface states, (iii) the modification of the band edge positions or band bending, and (iv) the selective extraction of carriers and improved catalytic activity. State-of-the-art surface treatments such as the adsorption of organic molecules or ions, the deposition of semiconductor overlayers and metal nanoparticles or etching procedures are exemplified and described with respect to the observed beneficial effects. A common emerging theme from recent work is that one single surface treatment can lead to multiple distinct effects. Overall, we suggest that surface engineering holds the key for effectively managing the intrinsic common defects of native semiconductor photoelectrodes regardless of their nature, leading to improved light harvesting efficiency.

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Section: Semiconductor Coatingmentioning

confidence: 94%

Surface modification of semiconductor photoelectrodes

Guijarro

Prévot

Sivula

2015

Phys. Chem. Chem. Phys.

144

123

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“…Gallium compounds12345 including gallium nitride (GaN), gallium oxide (Ga 2 O 3 ) and more recently gallium oxynitrides (GaON/Ga 3 O 3 N/Ga x O y N z ) have been known for their semiconducting and optoelectronic properties6789. These gallium materials in different morphologies have enlightened ample of applications e.g.…”

mentioning

confidence: 99%

Sonochemical Assisted Solvothermal Synthesis of Gallium Oxynitride Nanosheets and their Solar-Driven Photoelectrochemical Water-Splitting Applications

Iqbal

Khan

Yamani

et al. 2016

Sci Rep

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Gallium oxynitride (GaON) nanosheets for photoelectrochemical (PEC) analysis are synthesized via direct solvothermal approach. Their FE-SEM revealed nanosheets morphology of GaON prepared at a reaction time of 24 hours at 180 °C. The elemental composition and mapping of Ga, O and N are carried out through electron dispersive X-ray spectroscopy (EDX). The cubic structure of GaON nanosheets is elucidated by X-ray diffraction (XRD)analysis. The X-ray Photoelectron Spectroscopy (XPS) further confirms Ga, O and N in their respective ratios and states. The optical properties of GaON nanosheets are evaluated via UV-Visible, Photoluminescence (PL) and Raman spectroscopy’s. The band gap energy of ~1.9 eV is calculated from both absorption and diffused reflectance spectroscopy’s which showed stronger p-d repulsions in the Ga (3d) and N (2p) orbitals. This effect and chemical nitridation caused upward shift of valence band and band gap reduction. The GaON nanosheets are investigated for PEC studies in a standard three electrode system under 1 Sun irradiation in 0.5 M Na2SO4. The photocurrent generation, oxidation and reduction reactions during the measurements are observed by Chronoampereometry, linear sweep Voltametry (LSV) and Cyclic Voltametry (CV) respectively. Henceforward, these GaON nanosheets can be used as potential photocatalyts for solar water splitting.

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“…In the case of the photoanode, self-oxidation makes it difficult to utilize non-oxide materials. In contrast, the photocathode can be made of a non-oxide material, such as p-type Si [16][17][18][19], copper oxide [20,21], phosphides [22][23][24][25], and oxysulfides [26,27]. Most photocathodes showing a relatively high half-cell solar-to-hydrogen conversion efficiency (HC-STH) [28] have been composed of single-crystalline materials, as in the cases of Si, InP, and InGaP2, owing to their low defect densities; however, these electrodes require time-consuming and costly processes to fabricate.…”

Section: Introductionmentioning

confidence: 99%

Chalcopyrite Thin Film Materials for Photoelectrochemical Hydrogen Evolution from Water under Sunlight

2015

Self Cite

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Abstract:Copper chalcopyrite is a promising candidate for a photocathode material for photoelectrochemical (PEC) water splitting because of its high half-cell solar-to-hydrogen conversion efficiency (HC-STH), relatively simple and low-cost preparation process, and chemical stability. This paper reviews recent advances in copper chalcopyrite photocathodes. The PEC properties of copper chalcopyrite photocathodes have improved fairly rapidly: HC-STH values of 0.25% and 8.5% in 2012 and 2015, respectively. On the other hand, the onset potential remains insufficient, owing to the shallow valence band maximum mainly consisting of Cu 3d orbitals. In order to improve the onset potential, we explored substituting Cu for Ag and investigate the PEC properties of silver gallium selenide (AGSe) thin film photocathodes for varying compositions, film growth atmospheres, and surfaces. The modified AGSe photocathodes showed a higher onset potential than copper chalcopyrite photocathodes. It was demonstrated that element substitution of copper chalcopyrite can help to achieve more efficient PEC water splitting.

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Positive onset potential and stability of Cu₂O-based photocathodes in water splitting by atomic layer deposition of a Ga₂O₃buffer layer

Abstract: The improved energy band alignment of Pt/TiO2/Ga2O3/Cu2O structure results in a positive onset potential of ∼1 Vvs.RHE and a stable cathodic photocurrent under appropriate TiO2deposition temperature.

Cited by 209 publications

References 39 publications

Surface modification of semiconductor photoelectrodes

Surface modification of semiconductor photoelectrodes

Sonochemical Assisted Solvothermal Synthesis of Gallium Oxynitride Nanosheets and their Solar-Driven Photoelectrochemical Water-Splitting Applications

Chalcopyrite Thin Film Materials for Photoelectrochemical Hydrogen Evolution from Water under Sunlight

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