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Lo Presti F, Pellegrino AL, Micard Q, Condorelli GG, Margueron S, Bartasyte A, Malandrino G. LiNbO 3 Thin Films through a Sol-Gel/Spin-Coating Approach Using a Novel Heterobimetallic Lithium-Niobium Precursor. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:345. [PMID: 38392718 PMCID: PMC10892834 DOI: 10.3390/nano14040345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024]
Abstract
Lithium niobate is a lead-free material which has attracted considerable attention due to its excellent optical, piezoelectric, and ferroelectric properties. This research is devoted to the synthesis through an innovative sol-gel/spin-coating approach of polycrystalline LiNbO3 films on Si substrates. A novel single-source hetero-bimetallic precursor containing lithium and niobium was synthesized and applied to the sol-gel synthesis. The structural, compositional, and thermal characteristics of the precursor have been tested through attenuated total reflection, X-ray photoelectron spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The LiNbO3 films have been characterized from a structural point of view with combined X-ray diffraction and Raman spectroscopy. Field-emission scanning electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy have been used to study the morphological and compositional properties of the deposited films.
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Affiliation(s)
- Francesca Lo Presti
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, and INSTM UdR Catania, Viale Andrea Doria 6, I-95125 Catania, Italy; (F.L.P.); (A.L.P.); (G.G.C.)
| | - Anna Lucia Pellegrino
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, and INSTM UdR Catania, Viale Andrea Doria 6, I-95125 Catania, Italy; (F.L.P.); (A.L.P.); (G.G.C.)
| | - Quentin Micard
- FEMTO-ST Institute, University of Franche-Comté, ENSMM CNRS UMR 6174, 26 Rue de l’Epitaphe, F-25030 Besançon, France (S.M.); (A.B.)
| | - Guglielmo Guido Condorelli
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, and INSTM UdR Catania, Viale Andrea Doria 6, I-95125 Catania, Italy; (F.L.P.); (A.L.P.); (G.G.C.)
| | - Samuel Margueron
- FEMTO-ST Institute, University of Franche-Comté, ENSMM CNRS UMR 6174, 26 Rue de l’Epitaphe, F-25030 Besançon, France (S.M.); (A.B.)
| | - Ausrine Bartasyte
- FEMTO-ST Institute, University of Franche-Comté, ENSMM CNRS UMR 6174, 26 Rue de l’Epitaphe, F-25030 Besançon, France (S.M.); (A.B.)
- Institut Universitaire de France, 1 rue Descartes, F-75231 Paris, France
| | - Graziella Malandrino
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, and INSTM UdR Catania, Viale Andrea Doria 6, I-95125 Catania, Italy; (F.L.P.); (A.L.P.); (G.G.C.)
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Marni S, Nava G, Barboza R, Bellini TG, Lucchetti L. Walking Ferroelectric Liquid Droplets with Light. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2212067. [PMID: 36847158 DOI: 10.1002/adma.202212067] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/13/2023] [Indexed: 05/15/2023]
Abstract
The motion of ferroelectric liquid sessile droplets deposited on a ferroelectric lithium niobate substrate can be controlled by a light beam of moderate intensity irradiating the substrate at a distance of several droplet diameters from the droplet itself. The ferroelectric liquid is a nematic liquid crystal, in which almost complete polar ordering of the molecular dipoles generates an internal macroscopic polarization locally collinear to the mean molecular long axis. Upon entering the ferroelectric phase, droplets are either attracted toward the center of the beam or repelled, depending on the side of the lithium niobate exposed to light irradiation. Moreover, moving the beam results in walking the ferroelectric droplet over long distances on the substrate. This behavior is understood as due to the coupling between the polarization of the ferroelectric droplet and the polarization photoinduced in the irradiated region of the lithium niobate substrate. Indeed, the effect is not observed in the conventional nematic phase, suggesting the crucial role of the ferroelectric liquid crystal polarization.
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Affiliation(s)
- Stefano Marni
- Dipartimento SIMAU, Università Politecnica delle Marche, via Brecce Bianche, Ancona, 60131, Italy
| | - Giovanni Nava
- Medical Biotechnology and Translational Medicine Dept., University of Milano, Segrate, 20054, Italy
| | - Raouf Barboza
- Dipartimento SIMAU, Università Politecnica delle Marche, via Brecce Bianche, Ancona, 60131, Italy
| | - Tommaso Giovanni Bellini
- Medical Biotechnology and Translational Medicine Dept., University of Milano, Segrate, 20054, Italy
| | - Liana Lucchetti
- Dipartimento SIMAU, Università Politecnica delle Marche, via Brecce Bianche, Ancona, 60131, Italy
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Explosive electrostatic instability of ferroelectric liquid droplets on ferroelectric solid surfaces. Proc Natl Acad Sci U S A 2022; 119:e2207858119. [PMID: 35914148 PMCID: PMC9371712 DOI: 10.1073/pnas.2207858119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We investigated the electrostatic behavior of ferroelectric liquid droplets exposed to the pyroelectric field of a lithium niobate ferroelectric crystal substrate. The ferroelectric liquid is a nematic liquid crystal, in which almost complete polar ordering of the molecular dipoles generates an internal macroscopic polarization locally collinear to the mean molecular long axis. Upon entering the ferroelectric phase by reducing the temperature from the nematic phase, the liquid crystal droplets become electromechanically unstable and disintegrate by the explosive emission of fluid jets. These jets are mostly interfacial, spreading out on the substrate surface, and exhibit fractal branching out into smaller streams to eventually disrupt, forming secondary droplets. We understand this behavior as a manifestation of the Rayleigh instability of electrically charged fluid droplets, expected when the electrostatic repulsion exceeds the surface tension of the fluid. In this case, the charges are due to the bulk polarization of the ferroelectric fluid, which couples to the pyroelectric polarization of the underlying lithium niobate substrate through its fringing field and solid-fluid interface coupling. Since the ejection of fluid does not neutralize the droplet surfaces, they can undergo multiple explosive events as the temperature decreases.
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Chau YFC, Chang HE, Huang PS, Wu PC, Lim CM, Chiang LM, Wang TJ, Chao CTC, Kao TS, Shih MH, Chiang HP. Enhanced photoluminescence and shortened lifetime of DCJTB by photoinduced metal deposition on a ferroelectric lithography substrate. Sci Rep 2022; 12:6173. [PMID: 35418622 PMCID: PMC9007977 DOI: 10.1038/s41598-022-10303-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/30/2022] [Indexed: 11/09/2022] Open
Abstract
The photodeposition of metallic nanostructures onto ferroelectric surfaces could enable new applications based on the assembly of molecules and patterning local surface reactivity by enhancing surface field intensity. DCJTB (4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran) is an excellent fluorescent dye and dopant material with a high quantum efficiency used for OLED displays on the market. However, how to raise the photoluminescence (PL) and reduce the lifetime of DCJTB in a substrate remain extraordinary challenges for its application. Here, we demonstrate a tunable ferroelectric lithography plasmon-enhanced substrate to generate photo-reduced silver nanoparticles (AgNPs) and achieve enhanced PL with a shortened lifetime depending on the substrate's annealing time. The enhanced PL with shortened lifetimes can attribute to the localized electromagnetic (EM) wave produced by the nanotextured AgNPs layers' surface and gap plasmon resonances. The simulation is based on the three-dimensional finite element method to explain the mechanism of experimental results. Since the absorption increases, the remarkable enhanced PL of DCJTB can attain in the fabricated periodically proton exchanged (PPE) lithium niobate (LiNbO3) substrate. Furthermore, the proposed fabrication method demonstrates to help tune the surface EM wave distribution in the substrate, which can simultaneously achieve the significantly shortened lifetime and high PL intensity of DCJTB in the substrate. Compared with the un-annealed substrate, the PL intensity of DCJTB in the assembly metallic nanostructures is enhanced 13.70 times, and the PL's lifetime is reduced by 12.50%, respectively. Thus, the fabricated substrate can be a promising candidate, verifying chemically patterned ferroelectrics' satisfaction as a PL-active substrate.
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Affiliation(s)
- Yuan-Fong Chou Chau
- Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong, BE1410, Brunei Darussalam
| | - Hao-En Chang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan, ROC
| | - Po-Sheng Huang
- Department of Photonics, National Cheng Kung University, Tainan, 70101, Taiwan, ROC
| | - Pin Chieh Wu
- Department of Photonics, National Cheng Kung University, Tainan, 70101, Taiwan, ROC
| | - Chee Ming Lim
- Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong, BE1410, Brunei Darussalam
| | - Li-Ming Chiang
- Department of Photonics & Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan, ROC
| | - Tzyy-Jiann Wang
- Institute of Electro-Optical Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan, ROC
| | - Chung-Ting Chou Chao
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan, ROC
| | - Tsung Sheng Kao
- Department of Photonics & Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan, ROC
| | - Min-Hsiung Shih
- Research Center for Applied Sciences, Academia Sinica, Taipei, 11529, Taiwan, ROC
| | - Hai-Pang Chiang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan, ROC.
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State of the Art in Crystallization of LiNbO 3 and Their Applications. Molecules 2021; 26:molecules26227044. [PMID: 34834135 PMCID: PMC8617696 DOI: 10.3390/molecules26227044] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 11/16/2022] Open
Abstract
Lithium niobate (LiNbO3) crystals are important dielectric and ferroelectric materials, which are widely used in acoustics, optic, and optoelectrical devices. The physical and chemical properties of LiNbO3 are dependent on microstructures, defects, compositions, and dimensions. In this review, we first discussed the crystal and defect structures of LiNbO3, then the crystallization of LiNbO3 single crystal, and the measuring methods of Li content were introduced to reveal reason of growing congruent LiNbO3 and variable Li/Nb ratios. Afterwards, this review provides a summary about traditional and non-traditional applications of LiNbO3 crystals. The development of rare earth doped LiNbO3 used in illumination, and fluorescence temperature sensing was reviewed. In addition to radio-frequency applications, surface acoustic wave devices applied in high temperature sensor and solid-state physics were discussed. Thanks to its properties of spontaneous ferroelectric polarization, and high chemical stability, LiNbO3 crystals showed enhanced performances in photoelectric detection, electrocatalysis, and battery. Furthermore, domain engineering, memristors, sensors, and harvesters with the use of LiNbO3 crystals were formulated. The review is concluded with an outlook of challenges and potential payoff for finding novel LiNbO3 applications.
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Surface plasmon induced spot and line formation at interfaces of ITO coated LiNbO 3 slabs and gigantic nonlinearity. Sci Rep 2021; 11:19790. [PMID: 34611249 PMCID: PMC8492684 DOI: 10.1038/s41598-021-99270-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/14/2021] [Indexed: 11/08/2022] Open
Abstract
Remarkable spots and lines were clearly observed at the two interfaces of indium-tin-oxide coated Z-cut Fe-doped lithium noibate plates under illumination by milliwatt continuous-wave laser light; this occurred because of the visible surface plasmons (SPs) supported by the promising non-metal plasmonic system. The intriguing observations are here explained via the SP-strengthened nonlinear effect, through consideration of the electrostatic field (which is comparable to the atomic field) and its large gradient; this hints at a promising, highly sensitive plasmonic system. The gigantic nonlinear effect discussed in this paper should be ubiquitously existed in many oxide ferroelectric/semiconductor combinations and is promising for visible plasmonic applications.
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‘Horror Vacui’ in the Oxygen Sublattice of Lithium Niobate Made Affordable by Cationic Flexibility. CRYSTALS 2021. [DOI: 10.3390/cryst11070764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present review is intended for a broader audience interested in the resolution of the several decades-long controversy on the possible role of oxygen-vacancy defects in LiNbO3. Confronting ideas of a selected series of papers from classical experiments to brand new large-scale calculations, a unified interpretation of the defect generation and annealing mechanisms governing processes during thermo- and mechanochemical treatments and irradiations of various types is presented. The dominant role of as-grown and freshly generated Nb antisite defects as traps for small polarons and bipolarons is demonstrated, while mobile lithium vacancies, also acting as hole traps, are shown to provide flexible charge compensation needed for stability. The close relationship between LiNbO3 and the Li battery materials LiNb3O8 and Li3NbO4 is pointed out. The oxygen sublattice of the bulk plays a much more passive role, whereas oxygen loss and Li2O segregation take place in external or internal surface layers of a few nanometers.
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Real-Time Identification of Oxygen Vacancy Centers in LiNbO3 and SrTiO3 during Irradiation with High Energy Particles. CRYSTALS 2021. [DOI: 10.3390/cryst11030315] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Oxygen vacancies are known to play a central role in the optoelectronic properties of oxide perovskites. A detailed description of the exact mechanisms by which oxygen vacancies govern such properties, however, is still quite incomplete. The unambiguous identification of oxygen vacancies has been a subject of intense discussion. Interest in oxygen vacancies is not purely academic. Precise control of oxygen vacancies has potential technological benefits in optoelectronic devices. In this review paper, we focus our attention on the generation of oxygen vacancies by irradiation with high energy particles. Irradiation constitutes an efficient and reliable strategy to introduce, monitor, and characterize oxygen vacancies. Unfortunately, this technique has been underexploited despite its demonstrated advantages. This review revisits the main experimental results that have been obtained for oxygen vacancy centers (a) under high energy electron irradiation (100 keV–1 MeV) in LiNbO3, and (b) during irradiation with high-energy heavy (1–20 MeV) ions in SrTiO3. In both cases, the experiments have used real-time and in situ optical detection. Moreover, the present paper discusses the obtained results in relation to present knowledge from both the experimental and theoretical perspectives. Our view is that a consistent picture is now emerging on the structure and relevant optical features (absorption and emission spectra) of these centers. One key aspect of the topic pertains to the generation of self-trapped electrons as small polarons by irradiation of the crystal lattice and their stabilization by oxygen vacancies. What has been learned by observing the interplay between polarons and vacancies has inspired new models for color centers in dielectric crystals, models which represent an advancement from the early models of color centers in alkali halides and simple oxides. The topic discussed in this review is particularly useful to better understand the complex effects of different types of radiation on the defect structure of those materials, therefore providing relevant clues for nuclear engineering applications.
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Wang C, Su H, Ma X, Xiong Z, Zhao H. Young's double-slit-like diffraction stemming from scattering of long-ranged surface plasmon polaritons along distinct ±Z-faces' metallic layers in indium-tin-oxide coated Fe doped LiNbO 3. OPTICS LETTERS 2020; 45:6823-6826. [PMID: 33325905 DOI: 10.1364/ol.411510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Young's double-slit-like diffraction was seen on a viewing screen placed perpendicularly to a sharply cut edge of a Z-cut iron doped LiNbO3 (LN) slab coated with indium-tin-oxide (ITO) films. The high contrast fringes observed confirm two sets of visible long-ranged surface plasmon polaritons propagating along the two ITO-LN interfaces distinctly over 5 mm path length with well-kept coherency, apart from metal uses. The indices of refraction measured with polarimetry from the ±Z-faces and changing transmission spectra obtained are consistent with the physical picture, along with dynamics of the very first reflection from the -Z-face under varying polarization angles between the two incident laser beams onto the slab.
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Wang C, Su H, Ma X, Zhao H. Asymmetrical 1 st reflection trend owing to metallization difference at ± Z-faces in indium tin oxide coated Fe-doped lithium niobate. OPTICS EXPRESS 2020; 28:32042-32048. [PMID: 33115167 DOI: 10.1364/oe.404870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/30/2020] [Indexed: 06/11/2023]
Abstract
The charges accumulated at the interface of indium tin oxide (ITO) and iron doped lithium niobate (LN) in an extremely thin layer because of semiconductor band alignment were analyzed with ab initio theory. The formation of 2D electron gas makes the interface metallic and the excitation of surface plasmon polaritons (SPPs) possible. In experiments, diametrically opposite trends of the very first reflection (VFR) on the ± Z-faces of ITO coated Fe-LN slabs were observed and associated with the differences in metallization and the photovoltaic charge accumulation there. Microscopically, the electric environments of the two ITO/LN interfaces differ greatly owing to spontaneous polarization and photovoltaic fields, which alter the band structures and band alignment, resulting in phase gratings with a π-shift difference recorded at the two interfaces. This affects the opposite energy coupling between the SPPs and laser beams and results in the dramatically opposite trends of VFR.
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Swaisi M, Dörfler A, Katoch R, Ruediger A. Smooth pyroelectric luminescence in LiNbO 3 single crystals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:295701. [PMID: 32160601 DOI: 10.1088/1361-648x/ab7f03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We investigate the phenomenon of pyroelectric luminescence in LiNbO3 single crystals. This faint emission of light due to temperature-induced changes of permanent polarization is induced by different types of charge carrier recombination, outside and inside the crystal. With decreasing atmospheric pressure, the external discharge mechanism transitions from sparse intense gas discharge pulses at ambient pressure, to frequent faint discharges close to 1 mbar, to a continuous emission which is referred to as smooth pyroelectric luminescence. Our experimental setup exposes the crystal to constant positive and negative temperature changes in the range of 360-450 K under high vacuum while simultaneously measuring the surface charge density and the emitted intensity. A microscopic model of the luminescence allows the description of the time-dependent pyroelectric luminescence, in particular the determination of deep trap potentials that are otherwise inaccessible to thermal ionization. Using this model, we show that the behavior of this emission in LiNbO3 crystals is consistent with the release of trapped electrons by the Poole-Frenkel effect from a Dirac-well potential, while the commonly assumed coulombic trap shape is in clear disagreement with both the temporal evolution of the emission as well as the magnitude of the electric field obtained in our measurements.
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Affiliation(s)
- Mohamed Swaisi
- INRS-EMT, 1650 Blvd. Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada
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Zhao J, Rüsing M, Mookherjea S. Optical diagnostic methods for monitoring the poling of thin-film lithium niobate waveguides. OPTICS EXPRESS 2019; 27:12025-12038. [PMID: 31052748 DOI: 10.1364/oe.27.012025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
We demonstrate two non-destructive methods of studying the gradual poling of thin-film lithium niobate waveguides by the application of a sequence of high-voltage pulses, and we show the transition from under-poling to over-poling and the identification of the optimal stopping point of the poling process. The first diagnostic method is based on changes in continuous-wave light transmission through a hybrid waveguide as it is gradually poled by using a second set of monitoring electrodes fabricated alongside the principal poling electrodes. The second method is based on confocal back-reflected second-harmonic microscopy by using femtosecond optical probe pulses. The results from the two methods are in agreement with each other and may be useful as non-destructive in situ diagnostic methods for optimized poling of integrated waveguides.
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Dues C, Schmidt WG, Sanna S. Water Splitting Reaction at Polar Lithium Niobate Surfaces. ACS OMEGA 2019; 4:3850-3859. [PMID: 31459595 PMCID: PMC6648967 DOI: 10.1021/acsomega.8b03271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/25/2019] [Indexed: 06/10/2023]
Abstract
Water splitting is a highly promising, environmentally friendly approach for hydrogen production. It is often discussed in the context of carbon dioxide free combustion and storage of electrical energy after conversion to chemical energy. Since the oxidation and reduction reactions are related to significant overpotentials, the search for suitable catalysts is of particular importance. Ferroelectric materials, for example, lithium niobate, attracted considerable interest in this respect. Indeed, the presence of surfaces with different polarizations and chemistries leads to spatial separation of reduction and oxidation reactions, which are expected to be boosted by the electrons and holes available at the positive and negative surfaces, respectively. Employing the density functional theory and a simplified thermodynamic approach, we estimate the overpotentials related to the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) on both polar LiNbO3 (0001) surfaces. Our calculations performed for ideal surfaces in vacuum predict the lowest overpotential for the hydrogen evolution reaction (0.4 V) and for the oxygen evolution reaction (1.2 V) at the positive and at the negative surfaces, respectively, which are lower than (or comparable with) commonly employed catalysts. However, calculations performed to model the aqueous solution in which the reactions occur reveal that the presence of water substantially increases the required overpotential for the HER, even inverting the favorable polarization direction for oxidation and reduction reactions. In aqueous solution, we predict an overpotential of 1.2 V for the HER at the negative surface and 1.1 V for the OER at the positive surface.
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Affiliation(s)
- Christof Dues
- Institut
für Theoretische Physik and Center for Materials Research (LaMa), Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Wolf Gero Schmidt
- Department
Physik, Universität Paderborn, Warburger Str. 100, 33098 Paderborn, Germany
| | - Simone Sanna
- Institut
für Theoretische Physik and Center for Materials Research (LaMa), Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
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