Surface contributions to the XPS spectra of nanostructured NiO deposited on HOPG

Preda, I.; Mossanek, R. J. O.; Abbate, M.; Álvarez, Lucı́a; Méndez, Javier; Gutiérrez, Alejandro; Soriano, L.

doi:10.1016/j.susc.2012.05.005

Cited by 83 publications

(53 citation statements)

References 24 publications

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“…As to the other contributions to the overall Ni 2p envelope, we indicate here those appearing as a shoulder to the first peak mentioned above, unfolding in the range 855-860 eV. These two signals are associated to core-hole screening processes occurring at the surface, where the bulk symmetry is reduced and the coordination geometry around Ni is lowered from the octahedral NiO 6 to the square-pyramidal NiO 5[51,53,55].…”

mentioning

confidence: 57%

“…In order to account for the significantly increased presence of perchlorate anions after the oxidative treatment, one has to consider the redox behaviour of NiO. Electroactivity of bare NiO has been already reported both in aqueous and organic electrolytes [28,22,17,[47][48][49] These signals have been reported to be diagnostic of surface-confined relaxation processes [51,[55][56][57][58], and in many cases, have been naively associated to the presence of Ni 3+ defects [59,60].…”

Section: Pmentioning

confidence: 99%

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X-ray photoelectron spectroscopy investigation of nanoporous NiO electrodes sensitized with Erythrosine B

Bonomo

Marrani

Zanoni

2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Nanoporous NiO thin films were prepared onto FTO glass substrates by means of screen-printing and were sensitized with Erythrosine B (EryB) dye. The obtained material was electrochemically treated and characterized with ex-situ X-ray photoelectron spectroscopy in order to gain information beneficial to the application of sensitized NiO as photocathodes of p-type dye-sensitized solar cells (p-DSCs). In particular, EryB-sensitized NiO films underwent a series of electrochemical treatments in LiClO4/Acetonitrile (ACN) electrolyte devised so as to simulate possible conditions the electrode might encounter during operation in the photoelectrochemical cell. Upon potential-cycling in a range where the two NiO faradic events Ni(II)→Ni(III) and Ni(III)→Ni(IV) occur, X-ray photoelectron spectroscopy revealed that Erythrosine B dye experiences a partial detachment from the NiO surface. This detachment seems to be paralleled by the formation of stable (Ni)+(ClO4)- couples. Overall, the EryB dye displayed an acceptable electrochemical stability onto the surface of NiO electrode up to 50 cyclic voltammetries in the range -0.27÷+1.13V vs. Ag/AgCl. These results are useful for the evaluation of electrochemical stability of the dye when this is immobilized onto an electrode surface and are beneficial for a better comprehension of the degradation phenomena operating in real photoconversion device. © 2017 Elsevier B.V

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mentioning

confidence: 57%

Section: Pmentioning

confidence: 99%

X-ray photoelectron spectroscopy investigation of nanoporous NiO electrodes sensitized with Erythrosine B

Bonomo

Marrani

Zanoni

2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Besides, three more factors can complement this explanation helping to promote the copper oxidation: 1) metal nanoclusters tend to lose electrons and ionize; [ 51 ] 2) the reducing chemical nature of copper, which tends to reduce the oxides in contact with it becoming itself oxidized; and 3) zinc 3d orbitals are completely full, which induces less reactivity with O 2 and allows the presence of metal Zn even at such high pressures, two orders of magnitude higher than for other oxides, such as Co or Ni, using the same evaporation technique. [ 52,53 ] Thus, zinc is deposited on graphene first as a metal and only becomes oxidized once the oxidation process of copper has finished since all the intercalated species have been consumed (see Figure S2b, Supporting Information). Under this description, depending on the initial amount of intercalated species and the initial state of graphene (local work function values of graphene and copper and the initial electronic coupling between them), the thicknesses of the metal zinc deposit and the copper oxide layer can vary.…”

Section: Resultsmentioning

confidence: 99%

Electronic Decoupling of Graphene from Copper Induced by Deposition of ZnO: A Complex Substrate/Graphene/Deposit/Environment Interaction

Morales

Urbanos

Campo

et al. 2020

Adv Materials Inter

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has been a turning point in the study and application of 2D materials. In this sense, the very high ballistic transport distances of the order of the micron and very large carrier mobility [2][3][4] combined with the absorption of 2.3% of visible light, [5] places graphene as an extraordinary candidate for new optoelectronic devices. On the other hand, graphene's impermeability to most gases [6] makes it also a promising candidate for ultrathin passivation coating. [7] However, this idealistic view contrasts with the reduced number of real applications to industry and/or produced mass electronic devices. Without doubt, this frustrating fact is related to the difficulty to grow large areas of non-defective graphene, but also with the complexity of the interaction of graphene with other materials (substrates, multilayer systems) and/or media (gas, liquids) in contact with it, which leads to changes of the graphene properties.Focusing on this last point, the substrate plays a very important role in the electronic properties of graphene due to the strength of the bonding between both. As Weatherup et al. summarized, [7] depending on the position of the d valence band states with respect to the Fermi level, [8] two different interactions are reported for metallic substrates. In the case of Ni, Co, Fe, or Pd, the strong hybridization between π graphene states and metal d states leads to the destruction of the linear dispersion of graphene at the K point. For weak interactions, such as Cu, Au, Ag, and Pt, this linear dispersion is preserved but charge transfer between metal and graphene normally shifts the Fermi level position, leading to doping of graphene. Moreover, for SiC (0001) a covalent bonding between the substrate and the first carbon layer also prevents good electrical properties of graphene. [9,10] In all these cases, this interaction can be modulated or suppressed by controlled intercalation of metallic atoms at high temperatures, [11,12] or even at room temperature for alkaline elements. [13,14] The formation of an oxidized layer between substrate and graphene [15,16] can also decouple graphene from substrates.Nevertheless, the last description offers again a simplified view of the problem. The majority of the experimental and This study presents experimental data of the interactions and reactions that occur during the early stages of the growth of ZnO on graphene supported on polycrystalline copper and the subsequent changes on the electronic properties of the graphene. The combination of substrate, graphene, and intercalated species (such as oxygen and water molecules) between graphene and copper due to air exposure, together to the evaporation of metallic zinc under oxygen atmosphere, induces the electronic decoupling of the graphene from copper by the formation of a nanometric layer of copper oxide. In particular, the final stage consists in the formation of a complex interface formed by ZnO/ZnO 1−x /Zn/G/Cu 2 O/Cu. The role of each actor is discussed in terms of a galvanic corrosion reaction of the met...

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“…In previous works, we showed that the Ni 2p x-ray photoelectron spectral line shape of NiO is influenced by surface effects [12,13]. These effects are enhanced when the surface-to-volume ratio increases, as in nanostructured NiO [14,15], and are also present in the O 1s x-ray absorption spectra (XAS) of NiO [16,17].…”

Section: Introductionmentioning

confidence: 95%

Effects of Ni vacancies and crystallite size on the O 1s and Ni 2p x-ray absorption spectra of nanocrystalline NiO

Mossanek¹,

Domínguez-Cañizares²,

Gutiérrez³

et al. 2013

J. Phys.: Condens. Matter

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We have studied the electronic structure of nanocrystalline NiO thin films, grown by radio-frequency magnetron sputtering under different experimental conditions, using x-ray absorption spectroscopy. The O 1s and Ni 2p spectra showed distinct changes as a function of O2 content in the plasma, which were reproduced with cluster model calculations. These changes are attributed to the incrementing of the surface contribution due to a decrease of the crystallite size as the O2 content in the plasma increases, and to the presence of induced nickel vacancies. Thus, the changes in the electronic structure can be related to the modification of structural and transport properties of these nanocrystalline films.

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Surface contributions to the XPS spectra of nanostructured NiO deposited on HOPG

Cited by 83 publications

References 24 publications

X-ray photoelectron spectroscopy investigation of nanoporous NiO electrodes sensitized with Erythrosine B

X-ray photoelectron spectroscopy investigation of nanoporous NiO electrodes sensitized with Erythrosine B

Electronic Decoupling of Graphene from Copper Induced by Deposition of ZnO: A Complex Substrate/Graphene/Deposit/Environment Interaction

Effects of Ni vacancies and crystallite size on the O 1s and Ni 2p x-ray absorption spectra of nanocrystalline NiO

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