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Luna M, Barawi M, Gómez-Moñivas S, Colchero J, Rodríguez-Peña M, Yang S, Zhao X, Lu YH, Chintala R, Reñones P, Altoe V, Martínez L, Huttel Y, Kawasaki S, Weber-Bargioni A, de la Peña ÓShea VA, Yang P, Ashby PD, Salmeron M. Photoinduced Charge Transfer and Trapping on Single Gold Metal Nanoparticles on TiO 2. ACS APPLIED MATERIALS & INTERFACES 2021; 13:50531-50538. [PMID: 34641675 PMCID: PMC8554764 DOI: 10.1021/acsami.1c13662] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
We present a study of the effect of gold nanoparticles (Au NPs) on TiO2 on charge generation and trapping during illumination with photons of energy larger than the substrate band gap. We used a novel characterization technique, photoassisted Kelvin probe force microscopy, to study the process at the single Au NP level. We found that the photoinduced electron transfer from TiO2 to the Au NP increases logarithmically with light intensity due to the combined contribution of electron-hole pair generation in the space charge region in the TiO2-air interface and in the metal-semiconductor junction. Our measurements on single particles provide direct evidence for electron trapping that hinders electron-hole recombination, a key factor in the enhancement of photo(electro)catalytic activity.
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Affiliation(s)
- Monica Luna
- IMN-Instituto
de Micro y Nanotecnología (CNM-CSIC), 28760 Tres Cantos, Spain
| | - Mariam Barawi
- Photoactivated
Processes Unit, IMDEA-ENERGIA, 28935 Móstoles, Spain
| | - Sacha Gómez-Moñivas
- Departamento
de Ingeniería Informática, Escuela Politécnica
Superior, Universidad Autónoma de
Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Jaime Colchero
- Departamento
de Física, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
| | | | - Shanshan Yang
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
| | - Xiao Zhao
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
| | - Yi-Hsien Lu
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
| | - Ravi Chintala
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Patricia Reñones
- Photoactivated
Processes Unit, IMDEA-ENERGIA, 28935 Móstoles, Spain
| | - Virginia Altoe
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Lidia Martínez
- Instituto
de Ciencia de Materiales de Madrid (ICMM-CSIC), 28049 Madrid, Spain
| | - Yves Huttel
- Instituto
de Ciencia de Materiales de Madrid (ICMM-CSIC), 28049 Madrid, Spain
| | - Seiji Kawasaki
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
| | - Alexander Weber-Bargioni
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | | | - Peidong Yang
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Paul D. Ashby
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Miquel Salmeron
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
- Materials
Science and Engineering Department, University
of California Berkeley, Berkeley, California 94720, United States
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2
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Xiang F, Schmitt T, Raschmann M, Schneider MA. Adsorption and self-assembly of porphyrins on ultrathin CoO films on Ir(100). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1516-1524. [PMID: 33094085 PMCID: PMC7554680 DOI: 10.3762/bjnano.11.134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Porphyrins represent a versatile class of molecules, the adsorption behavior of which on solid surfaces is of fundamental interest due to a variety of potential applications. We investigate here the molecule-molecule and molecule-substrate interaction of Co-5,15-diphenylporphyrin (Co-DPP) and 2H-tetrakis(p-cyanophenyl)porphyrin (2H-TCNP) on one bilayer (1BL) and two bilayer (2BL) thick cobalt oxide films on Ir(100) by scanning tunneling microscopy (STM) and density functional theory (DFT). The two substrates differ greatly with respect to their structural and potential-energy landscape corrugation with immediate consequences for adsorption and self-assembly of the molecules studied. On both films, an effective electronic decoupling from the metal substrate is achieved. However, on the 1BL film, Co-DPP molecules are sufficiently mobile at 300 K and coalesce to self-assembled molecular islands when cooled to 80 K despite their rather weak intermolecular interaction. In contrast, on the 2BL film, due to the rather flat potential landscape, molecular rotation is thermally activated, which effectively prevents self-assembly. The situation is different for 2H-TCNPP, which, due to the additional functional anchoring groups, does not self-assemble on the 1BL film but forms self-assembled compact islands on the 2BL film. The findings demonstrate the guiding effect of the cobalt oxide films of different thickness and the effect of functional surface anchoring.
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Affiliation(s)
- Feifei Xiang
- Solid State Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Tobias Schmitt
- Solid State Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Marco Raschmann
- Solid State Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - M Alexander Schneider
- Solid State Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
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3
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Wähler T, Schuster R, Libuda J. Self-Metalation of Anchored Porphyrins on Atomically Defined Cobalt Oxide Surfaces: In situ Studies by Surface Vibrational Spectroscopy. Chemistry 2020; 26:12445-12453. [PMID: 32333716 PMCID: PMC7590103 DOI: 10.1002/chem.202001331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Indexed: 12/20/2022]
Abstract
Metalation of anchored porphyrins is essential for their functionality at hybrid interfaces. In this work, we have studied the anchoring and metalation of a functionalized porphyrin derivative, 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin (MCTPP), on an atomically-defined CoO(100) film under ultrahigh vacuum (UHV) conditions. We follow both the anchoring to the oxide surface and the self-metalation by surface Co2+ ions via infrared reflection absorption spectroscopy (IRAS). At 150 K, MCTPP multilayer films adsorb molecularly on CoO(100) without anchoring to the surface. Upon heating to 195 K, the first layer of porphyrin molecules anchors via formation of a bridging surface carboxylate. Above 460 K, the MCTPP multilayer desorbs and only the anchored monolayer resides on the surface up to temperatures of 600 K approximately. The orientation of anchored MCTPP depends on the surface coverage. At low coverage, the MCTPP adopts a nearly flat-lying geometry, whereas an upright standing film is formed near the multilayer coverage. Self-metalation of MCTPP depends critically on the surface temperature, the coverage and on the molecular orientation. At 150 K, metalation is largely suppressed, while the degree of metalation increases with increasing temperature and reaches a value of around 60 % in the first monolayer at 450 K. At lower coverage higher metalation fractions (85 % and above) are observed, similar as for increasing temperature.
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Affiliation(s)
- Tobias Wähler
- Interface Research and CatalysisErlangen Center for Interface Research and Catalysis (ECRC)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
| | - Ralf Schuster
- Interface Research and CatalysisErlangen Center for Interface Research and Catalysis (ECRC)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
| | - Jörg Libuda
- Interface Research and CatalysisErlangen Center for Interface Research and Catalysis (ECRC)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
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4
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Freund S, Hinaut A, Marinakis N, Constable EC, Meyer E, Housecroft CE, Glatzel T. Comparing a porphyrin- and a coumarin-based dye adsorbed on NiO(001). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:874-881. [PMID: 31165014 PMCID: PMC6541355 DOI: 10.3762/bjnano.10.88] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/03/2019] [Indexed: 06/09/2023]
Abstract
Properties of metal oxides, such as optical absorption, can be influenced through the sensitization with molecular species that absorb visible light. Molecular/solid interfaces of this kind are particularly suited for the development and design of emerging hybrid technologies such as dye-sensitized solar cells. A key optimization parameter for such devices is the choice of the compounds in order to control the direction and the intensity of charge transfer across the interface. Here, the deposition of two different molecular dyes, porphyrin and coumarin, as single-layered islands on a NiO(001) single crystal surface have been studied by means of non-contact atomic force microscopy at room temperature. Comparison of both island types reveals different adsorption and packing of each dye, as well as an opposite charge-transfer direction, which has been quantified by Kelvin probe force microscopy measurements.
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Affiliation(s)
- Sara Freund
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Nathalie Marinakis
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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