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Acelas M, Castellanos NJ, Sierra CA. Stability and Performance Enhancement of an Oligo (phenylene vinylene) Photocatalyst via Surface Grafting onto TiO
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for Visible‐Light Indigo Carmine Degradation. ChemistrySelect 2022. [DOI: 10.1002/slct.202103460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mauricio Acelas
- Grupo de Investigación en Macromoléculas Departamento de Química Universidad Nacional de Colombia Bogotá 111321 Colombia
| | - Nelson J. Castellanos
- Estado Sólido y Catálisis Ambiental (ESCA) Departamento de Química Universidad Nacional de Colombia Bogotá 111321 Colombia
| | - César A. Sierra
- Grupo de Investigación en Macromoléculas Departamento de Química Universidad Nacional de Colombia Bogotá 111321 Colombia
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Loiudice A, Segura Lecina O, Bornet A, Luther JM, Buonsanti R. Ligand Locking on Quantum Dot Surfaces via a Mild Reactive Surface Treatment. J Am Chem Soc 2021; 143:13418-13427. [PMID: 34375098 DOI: 10.1021/jacs.1c06777] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
At the outermost surface of colloidal QDs are organic surface ligands which dynamically bind and release in solution to control the growth kinetics, control the size/shape of the crystals, passivate surface states, and provide colloidal stability through favorable interactions with the solvent. However, the dynamicity comes at the expense of the stability of the QD suspension. Here, we show that ligands can be permanently locked on the QD surface by a thin layer of an inert metal oxide which forms within the ligand shell, over the headgroup. By interrogating the surface chemistry with different spectroscopic methods, we prove the ligand locking on the QD surface. As a result, an exceptional stability of the coated QD inks is achieved in a wide concentration range, even in the presence of chemically competing surface ligands in solution. We anticipate that this critical breakthrough will benefit different areas related to colloidal QDs, spanning from single-particle studies to displays and solar cells and biological applications. Furthermore, the same chemistry could be easily translated to surface treatments of bulk materials and thin films.
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Affiliation(s)
- Anna Loiudice
- Laboratory of Nanochemistry for Energy Research, Institute of Chemical Sciences and Engineering, Ecole Politechnique Fédérale de Lausanne, Sion CH-1950, Switzerland
| | - Ona Segura Lecina
- Laboratory of Nanochemistry for Energy Research, Institute of Chemical Sciences and Engineering, Ecole Politechnique Fédérale de Lausanne, Sion CH-1950, Switzerland
| | - Aurélien Bornet
- Institute of Chemical Sciences and Engineering, Ecole Politechnique Fédérale de Lausanne, Sion CH-1950, Switzerland
| | - Joseph M Luther
- National Renewable Energy Laboratory (NREL), Golden, Colorado 80401, United States
| | - Raffaella Buonsanti
- Laboratory of Nanochemistry for Energy Research, Institute of Chemical Sciences and Engineering, Ecole Politechnique Fédérale de Lausanne, Sion CH-1950, Switzerland
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Zhang H, Weiss I, Rudra I, Jo WJ, Kellner S, Katsoukis G, Galoppini E, Frei H. Controlling and Optimizing Photoinduced Charge Transfer across Ultrathin Silica Separation Membrane with Embedded Molecular Wires for Artificial Photosynthesis. ACS APPLIED MATERIALS & INTERFACES 2021; 13:23532-23546. [PMID: 33983702 DOI: 10.1021/acsami.1c00735] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ultrathin amorphous silica membranes with embedded organic molecular wires (oligo(p-phenylenevinylene), three aryl units) provide chemical separation of incompatible catalytic environments of CO2 reduction and H2O oxidation while maintaining electronic and protonic coupling between them. For an efficient nanoscale artificial photosystem, important performance criteria are high rate and directionality of charge flow. Here, the visible-light-induced charge flow from an anchored Ru bipyridyl light absorber across the silica nanomembrane to Co3O4 water oxidation catalyst is quantitatively evaluated by photocurrent measurements. Charge transfer rates increase linearly with wire density, with 5 nm-2 identified as an optimal target. Accurate measurement of wire and light absorber densities is accomplished by the polarized FT-IRRAS method. Guided by density functional theory (DFT) calculations, four wire derivatives featuring electron-donating (methoxy) and -withdrawing groups (sulfonate, perfluorophenyl) with highest occupied molecular orbital (HOMO) potentials ranging from 1.48 to 0.64 V vs NHE were synthesized and photocurrents evaluated. Charge transfer rates increase sharply with increasing driving force for hole transfer from the excited light absorber to the embedded wire, followed by a decrease as the HOMO potential of the wire moves beyond the Co3O4 valence band level toward more negative values, pointing to an optimal wire HOMO potential around 1.3 V vs NHE. Comparison with photocurrents of samples without nanomembrane indicates that silica layers with optimized wires are able to approach undiminished electron flux at typical solar intensities. Combined with the established high proton conductivity and small-molecule blocking property, the charge transfer measurements demonstrate that oxidation and reduction catalysis can be efficiently integrated on the nanoscale under separation by an ultrathin silica membrane.
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Affiliation(s)
- Hongna Zhang
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, United States
| | - Ian Weiss
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, United States
| | - Indranil Rudra
- Shell India Markets Pvt. Ltd., Mahadeva Kodigehalli, Bangalore 562149, India
| | - Won Jun Jo
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, United States
| | - Simon Kellner
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, United States
| | - Georgios Katsoukis
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, United States
| | - Elena Galoppini
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, United States
| | - Heinz Frei
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, United States
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Livshits MY, Turlington MD, Trindle CO, Wang L, Altun Z, Wagenknecht PS, Rack JJ. Picosecond to Nanosecond Manipulation of Excited-State Lifetimes in Complexes with an Fe II to Ti IV Metal-to-Metal Charge Transfer: The Role of Ferrocene Centered Excited States. Inorg Chem 2019; 58:15320-15329. [PMID: 31686500 DOI: 10.1021/acs.inorgchem.9b02316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-resolved transient absorption spectroscopy and computational analysis of D-π-A complexes comprising FeII donors and TiIV acceptors with the general formula RCp2Ti(C2Fc)2 (where RCp = Cp*, Cp, and MeOOCCp) and TMSCp2Ti(C2Fc)(C2R) (where R = Ph or CF3) are reported. The transient absorption spectra are consistent with an FeIII/TiIII metal-to-metal charge-transfer (MMCT) excited state for all complexes. Thus, excited-state decay is assigned to back-electron transfer (BET), the lifetime of which ranges from 18.8 to 41 ps. Though spectroscopic analysis suggests BET should fall into the Marcus inverted regime, the observed kinetics are not consistent with this assertion. TDDFT calculations reveal that the singlet metal-to-metal charge-transfer (1MMCT) excited state for the FeII/TiIV complexes is not purely MMCT in nature but is contaminated with the higher-energy 1Fc (d-d) state. For the diferrocenyl complexes, RCp2Ti(C2Fc)2, the ratio of MMCT to Fc centered character ranges from 57:43 for the Cp* complex to 85:15 for the MeOOCCp complex. For the diferrocenyl and monoferrocenyl complexes investigated herein, the excited-state lifetimes decrease with increased 1Fc character. The effect of CuI coordination was also analyzed by time-resolved transient absorption spectroscopy and reveals the elongation of the excited-state lifetime by 3 orders of magnitude to 63 ns. The transient spectra and TDDFT analysis suggest that the long-lived excited state in Cp2Ti(C2Fc)2·CuX (where X is Cl or Br) is a triplet iron species with an electron arrangement of TiIV-3FeII-CuI.
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Affiliation(s)
- Maksim Y Livshits
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Michael D Turlington
- Department of Chemistry , Furman University , Greenville , South Carolina 29613 , United States
| | - Carl O Trindle
- Department of Chemistry , University of Virginia , Charlottesville , Virginia 22904 , United States
| | - Lei Wang
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Zikri Altun
- Department of Physics , Marmara University , Göztepe Kampus , 34772 Istanbul , Turkey
| | - Paul S Wagenknecht
- Department of Chemistry , Furman University , Greenville , South Carolina 29613 , United States
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
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Katsoukis G, Frei H. Ultrathin oxide layers for nanoscale integration of molecular light absorbers, catalysts, and complete artificial photosystems. J Chem Phys 2019; 150:041501. [DOI: 10.1063/1.5052453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Georgios Katsoukis
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - Heinz Frei
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
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