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Onur E, Lee J, Aymerich-Armengol R, Lim J, Dai Y, Tüysüz H, Scheu C, Weidenthaler C. Exploring the Effects of the Photochromic Response and Crystallization on the Local Structure of Noncrystalline Niobium Oxide. ACS APPLIED MATERIALS & INTERFACES 2024; 16:25136-25147. [PMID: 38687307 PMCID: PMC11103654 DOI: 10.1021/acsami.4c04038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/19/2024] [Accepted: 04/24/2024] [Indexed: 05/02/2024]
Abstract
Niobium oxide (Nb2O5) is a versatile semiconductor material with photochromic properties. This study investigates the local structure of noncrystalline, short-range-ordered niobium oxide synthesized via a sol-gel method. X-ray atomic pair distribution function analysis unravels the structural arrangements within the noncrystalline materials at a local scale. In the following, in situ scattering and diffraction experiments elucidate the heat-induced structure transformation of the amorphous material into crystalline TT-Nb2O5 at 550 °C. In addition, the effect of photocatalytic conditions on the structure of the material was investigated by exposing the short-range-ordered and crystalline materials to ultraviolet light, resulting in a reversible color change from white to dark brown or blue. This photochromic response is due to the reversible elongation of the nearest Nb-O neighbors, as shown by local structure analysis based on in situ PDF analyses. Optical band gap calculations based on the ultraviolet-visible spectra collected for both the short-range-ordered and crystalline materials show that the band gap values reduced for the darkened materials return to their initial state after bleaching. Furthermore, electron energy loss spectroscopy reveals the reduction of Nb5+ to Nb4+ centers as a persistent effect. The study establishes a correlation between the band gap and the structure of niobium oxide, providing insights into the structure-performance relation at the atomic level.
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Affiliation(s)
- Ezgi Onur
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Jinsun Lee
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | | | - Joohyun Lim
- Max-Planck-Institut
für Eisenforschung, Max-Planck-Straße 1, 40237 Düsseldorf, Germany
| | - Yitao Dai
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Harun Tüysüz
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Christina Scheu
- Max-Planck-Institut
für Eisenforschung, Max-Planck-Straße 1, 40237 Düsseldorf, Germany
| | - Claudia Weidenthaler
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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Recalde-Benitez O, Pivak Y, Winkler R, Jiang T, Adabifiroozjaei E, Perez-Garza HH, Molina-Luna L. Multi-Stimuli Operando Transmission Electron Microscopy for Two-Terminal Oxide-Based Devices. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2024; 30:200-207. [PMID: 38526872 DOI: 10.1093/mam/ozae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 01/30/2024] [Accepted: 03/02/2024] [Indexed: 03/27/2024]
Abstract
The integration of microelectromechanical systems (MEMS)-based chips for in situ transmission electron microscopy (TEM) has emerged as a highly promising technique in the study of nanoelectronic devices within their operational parameters. This innovative approach facilitates the comprehensive exploration of electrical properties resulting from the simultaneous exposure of these devices to a diverse range of stimuli. However, the control of each individual stimulus within the confined environment of an electron microscope is challenging. In this study, we present novel findings on the effect of a multi-stimuli application on the electrical performance of TEM lamella devices. To approximate the leakage current measurements of macroscale electronic devices in TEM lamellae, we have developed a postfocused ion beam (FIB) healing technique. This technique combines dedicated MEMS-based chips and in situ TEM gas cells, enabling biasing experiments under environmental conditions. Notably, our observations reveal a reoxidation process that leads to a decrease in leakage current for SrTiO3-based memristors and BaSrTiO3-based tunable capacitor devices following ion and electron bombardment in oxygen-rich environments. These findings represent a significant step toward the realization of multi-stimuli TEM experiments on metal-insulator-metal devices, offering the potential for further exploration and a deeper understanding of their intricate behavior.
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Affiliation(s)
- Oscar Recalde-Benitez
- Advanced Electron Microscopy Division, Institute of Materials Science, Department of Materials and Geosciences, Technische Universität Darmstadt, Peter-Grünber-strasse 2, Darmstadt 64287, Germany
| | - Yevheniy Pivak
- DENSsolutions BV, Informaticalaan 12, Delft 2628 ZD, The Netherlands
| | - Robert Winkler
- Advanced Electron Microscopy Division, Institute of Materials Science, Department of Materials and Geosciences, Technische Universität Darmstadt, Peter-Grünber-strasse 2, Darmstadt 64287, Germany
| | - Tianshu Jiang
- Advanced Electron Microscopy Division, Institute of Materials Science, Department of Materials and Geosciences, Technische Universität Darmstadt, Peter-Grünber-strasse 2, Darmstadt 64287, Germany
| | - Esmaeil Adabifiroozjaei
- Advanced Electron Microscopy Division, Institute of Materials Science, Department of Materials and Geosciences, Technische Universität Darmstadt, Peter-Grünber-strasse 2, Darmstadt 64287, Germany
| | | | - Leopoldo Molina-Luna
- Advanced Electron Microscopy Division, Institute of Materials Science, Department of Materials and Geosciences, Technische Universität Darmstadt, Peter-Grünber-strasse 2, Darmstadt 64287, Germany
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Bathe AS, Sanz Arjona A, Regan A, Wallace C, Nerney CR, O'Donoghue N, Crosland JM, Simonian T, Walton RI, Dunne PW. Solvothermal synthesis of soluble, surface modified anatase and transition metal doped anatase hybrid nanocrystals. NANOSCALE ADVANCES 2022; 4:5343-5354. [PMID: 36540114 PMCID: PMC9724697 DOI: 10.1039/d2na00640e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023]
Abstract
Titanium dioxide, or titania, is perhaps the most well-known and widely studied photocatalytic material, with myriad applications, due to a high degree of tunability achievable through the incorporation of dopants and control of phase composition and particle size. Many of the applications of titanium dioxide require particular forms, such as gels, coatings, or thin films, making the development of hybrid solution processable nanoparticles increasingly attractive. Here we report a simple solvothermal route to highly dispersible anatase phase titanium dioxide hybrid nanoparticles from amorphous titania. Solvothermal treatment of the amorphous titania in trifluoroacetic acid leads to the formation of anatase phase nanoparticles with a high degree of size control and near complete surface functionalisation. This renders the particles highly dispersible in simple organic solvents such as acetone. Dopant ions may be readily incorporated into the amorphous precursor by co-precipitation, with no adverse effect on subsequent crystallisation and surface modification.
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Affiliation(s)
- A S Bathe
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
| | - A Sanz Arjona
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
| | - A Regan
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
- CDT ACM, AMBER, Trinity College Dublin, College Green Dublin 2 Ireland
| | - C Wallace
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
| | - C R Nerney
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
| | - N O'Donoghue
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
| | - J M Crosland
- School of Chemistry, University of Warwick Gibbet Hill Coventry CV4 7AL UK
| | - T Simonian
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
- CDT ACM, AMBER, Trinity College Dublin, College Green Dublin 2 Ireland
| | - R I Walton
- School of Chemistry, University of Warwick Gibbet Hill Coventry CV4 7AL UK
| | - P W Dunne
- School of Chemistry, Trinity College Dublin, College Green Dublin 2 Ireland
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Onur Şahin E, Dai Y, Chan CK, Tüysüz H, Schmidt W, Lim J, Zhang S, Scheu C, Weidenthaler C. Monitoring the Structure Evolution of Titanium Oxide Photocatalysts: From the Molecular Form via the Amorphous State to the Crystalline Phase. Chemistry 2021; 27:11600-11608. [PMID: 34060158 PMCID: PMC8456846 DOI: 10.1002/chem.202101117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Indexed: 11/07/2022]
Abstract
Amorphous Tix Oy with high surface area has attracted significant interest as photocatalyst with higher activity in ultraviolet (UV) light-induced water splitting applications compared to commercial nanocrystalline TiO2 . Under photocatalytic operation conditions, the structure of the molecular titanium alkoxide precursor rearranges upon hydrolysis and leads to higher connectivity of the structure-building units. Structurally ordered domains with sizes smaller than 7 Å form larger aggregates. The experimental scattering data can be explained best with a structure model consisting of an anatase-like core and a distorted shell. Upon exposure to UV light, the white Tix Oy suspension turns dark corresponding to the reduction of Ti4+ to Ti3+ as confirmed by electron energy loss spectroscopy (EELS). Heat-induced crystallisation was followed by in situ temperature-dependent total scattering experiments. First, ordering in the Ti-O environment takes place upon to 350 °C. Above this temperature, the distorted anatase core starts to grow but the structure obtained at 400 °C is still not fully ordered.
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Affiliation(s)
- Ezgi Onur Şahin
- Heterogeneous CatalysisMax-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Yitao Dai
- Heterogeneous CatalysisMax-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Candace K. Chan
- Heterogeneous CatalysisMax-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
- Materials Science and EngineeringSchool for Engineering of MatterTransport and Energy (SEMTE)Arizona State UniversityAZ 85287-8706TempeUSA
| | - Harun Tüysüz
- Heterogeneous CatalysisMax-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Wolfgang Schmidt
- Heterogeneous CatalysisMax-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Joohyun Lim
- Nanoanalytics and InterfacesMax-Planck-Institut für Eisenforschung GmbHMax-Planck-Straße 140237DüsseldorfGermany
- Department of ChemistryKangwon National University24341ChuncheonRepublic of Korea
| | - Siyuan Zhang
- Nanoanalytics and InterfacesMax-Planck-Institut für Eisenforschung GmbHMax-Planck-Straße 140237DüsseldorfGermany
| | - Christina Scheu
- Nanoanalytics and InterfacesMax-Planck-Institut für Eisenforschung GmbHMax-Planck-Straße 140237DüsseldorfGermany
| | - Claudia Weidenthaler
- Heterogeneous CatalysisMax-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
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