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Pal R, Billah M, Rangarajan G, Farnood R. Crystal strain engineering of AgBr/TiO2 for visible-light photocatalysis: Balancing light absorption and charge carrier kinetics. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2023.114688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
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Debgupta J, Lari L, Isaacs M, Carey J, McKenna KP, Lazarov VK, Chechik V, Douthwaite RE. Predictive Removal of Interfacial Defect-Induced Trap States between Titanium Dioxide Nanoparticles via Sub-Monolayer Zirconium Coating. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:660-671. [PMID: 36660098 PMCID: PMC9841567 DOI: 10.1021/acs.jpcc.2c06927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/13/2022] [Indexed: 06/17/2023]
Abstract
First principles modeling of anatase TiO2 surfaces and their interfacial contacts shows that defect-induced trap states within the band gap arise from intrinsic structural distortions, and these can be corrected by modification with Zr(IV) ions. Experimental testing of these predictions has been undertaken using anatase nanocrystals modified with a range of Zr precursors and characterized using structural and spectroscopic methods. Continuous-wave electron paramagnetic resonance (EPR) spectroscopy revealed that under illumination, nanoparticle-nanoparticle interfacial hole trap states dominate, which are significantly reduced after optimizing the Zr doping. Fabrication of nanoporous films of these materials and charge injection using electrochemical methods shows that Zr doping also leads to improved electron conductivity and mobility in these nanocrystalline systems. The simple methodology described here to reduce the concentration of interfacial defects may have wider application to improving the efficiency of systems incorporating metal oxide powders and films including photocatalysts, photovoltaics, fuel cells, and related energy applications.
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Affiliation(s)
| | - Leonardo Lari
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Mark Isaacs
- HarwellXPS, R92 Research Complex at Harwell, Rutherford Appleton Laboratories,
Harwell, Didcot OX11 0QS, UK
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - John Carey
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Keith P. McKenna
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Vlado K. Lazarov
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Victor Chechik
- Department
of Chemistry, University of York, York YO10 5DD, UK
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Dittrich T, Sydorenko J, Spalatu N, Nickel NH, Mere A, Krunks M, Oja Acik I. Synthesis Control of Charge Separation at Anatase TiO 2 Thin Films Studied by Transient Surface Photovoltage Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2022; 14:43163-43170. [PMID: 36100206 PMCID: PMC9523608 DOI: 10.1021/acsami.2c09032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
For the efficient photocatalytic oxidation of organic pollutants at surfaces of semiconductors, photogenerated holes shall be separated toward the surface and transferred to reactive surface sites, whereas the transfer of photogenerated electrons toward the surface shall be minimized. In this Research Article, the identification of suitable synthesis control of charge separation combined with an in-depth understanding of charge kinetics and trapping passivation mechanisms at the related surfaces can provide tremendous opportunities for boosting the photocatalytic performance. In this work, a comprehensive transient surface photovoltage spectroscopy study of charge separation at anatase TiO2 thin films, synthesized by ultrasonic spray pyrolysis from titanium(IV) isopropoxide (TTIP)-acetylacetone (AcacH) based precursor is reported. By varying the amount of AcacH in the precursor solution, an experimental approach of synthesis control of the charge transfer toward TiO2 surface is provided for the first time. An increased amount of AcacH in the precursor promotes transition from preferential fast electron to preferential fast hole transfer toward anatase surface, correlating with a strong increase of the photocatalytic decomposition rate of organic pollutants. Suitable mechanisms of AcacH-induced passivation of electron traps at TiO2 surfaces are analyzed, providing a new degree of freedom for tailoring the properties of photocatalytic systems.
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Affiliation(s)
- Thomas Dittrich
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, Institut für Silizium-Photovoltaik, Kekuléstr. 5, D-12489 Berlin, Germany
| | - Jekaterina Sydorenko
- Tallinn
University of Technology, Department of Materials
and Environmental Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Nicolae Spalatu
- Tallinn
University of Technology, Department of Materials
and Environmental Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Norbert H. Nickel
- Helmholtz
Zentrum Berlin für Materialien und Energie GmbH, Institut für Silizium-Photovoltaik, Kekuléstr. 5, D-12489 Berlin, Germany
| | - Arvo Mere
- Tallinn
University of Technology, Department of Materials
and Environmental Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Malle Krunks
- Tallinn
University of Technology, Department of Materials
and Environmental Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Ilona Oja Acik
- Tallinn
University of Technology, Department of Materials
and Environmental Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
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Koltsov M, Krautmann R, Katerski A, Maticiuc N, Krunks M, Oja Acik I, Spalatu N. A post-deposition annealing approach for organic residues control in TiO2 and its impact on Sb2Se3/TiO2 device performance. Faraday Discuss 2022; 239:273-286. [DOI: 10.1039/d2fd00064d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a systematic investigation on the influence of the two-step post-deposition treatments (PDTs) on TiO2 buffer layers deposited by ultrasonic spray pyrolysis (USP) for emerging Sb2Se3 photovoltaics. Air annealing...
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