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Healing G, Nadinov I, Hadmojo WT, Yin J, Thomas S, Bakr OM, Alshareef HN, Anthopoulos TD, Mohammed OF. Ultrafast Coherent Hole Injection at the Interface between CuSCN and Polymer PM6 Using Femtosecond Mid-Infrared Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38573046 DOI: 10.1021/acsami.4c01156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Tracking the dynamics of ultrafast hole injection into copper thiocyanate (CuSCN) at the interface can be experimentally challenging. These challenges include restrictions in accessing the ultraviolet spectral range through transient electronic spectroscopy, where the absorption spectrum of CuSCN is located. Time-resolved vibrational spectroscopy solves this problem by tracking marker modes at specific frequencies and allowing direct access to dynamical information at the molecular level at donor-acceptor interfaces in real time. This study uses photoabsorber PM6 (poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)-benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))]) as a model system to explore and decipher the hole transfer dynamics of CuSCN using femtosecond (fs) mid-infrared (IR) spectroscopy. The time-resolved results indicate that excited PM6 exhibits a sharp vibrational mode at 1599 cm-1 attributed to the carbonyl group, matching the predicted frequency position obtained from time-dependent density functional theory (DFT) calculations. The fs mid-IR spectroscopy demonstrates a fast formation (<168 fs) and blue spectral shift of the CN stretching vibration from 2118 cm-1 for CuSCN alone to 2180 cm-1 for PM6/CuSCN, confirming the hole transfer from PM6 to CuSCN. The short interfacial distance and high frontier orbital delocalization obtained from the interfacial DFT models support a coherent and ultrafast regime for hole transfer. These results provide direct evidence for hole injection at the interface of CuSCN for the first time using femtosecond mid-IR spectroscopy and serve as a new investigative approach for interfacial chemistry and solar cell communities.
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Affiliation(s)
- George Healing
- Advanced Membranes and Porous Materials Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
- KAUST Catalysis Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Issatay Nadinov
- Advanced Membranes and Porous Materials Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Wisnu Tantyo Hadmojo
- KAUST Solar Center, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Jun Yin
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Simil Thomas
- Advanced Membranes and Porous Materials Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Osman M Bakr
- KAUST Catalysis Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Husam N Alshareef
- Materials Science and Engineering, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Thomas D Anthopoulos
- KAUST Solar Center, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Omar F Mohammed
- Advanced Membranes and Porous Materials Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
- KAUST Catalysis Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
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Segatta F, Aranda D, Aleotti F, Montorsi F, Mukamel S, Garavelli M, Santoro F, Nenov A. Time-Resolved X-ray Absorption Spectroscopy: An MCTDH Quantum Dynamics Protocol. J Chem Theory Comput 2024; 20:307-322. [PMID: 38101807 PMCID: PMC10782456 DOI: 10.1021/acs.jctc.3c00953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/04/2023] [Accepted: 11/09/2023] [Indexed: 12/17/2023]
Abstract
Expressions for linear and nonlinear spectroscopy simulation in the X-ray window in which the time evolution of a photoexcited molecular system is treated via quantum dynamics are derived. By leveraging on the peculiar properties of core-excited/ionized states, first- and third-order response functions are recast in the limit of time-scale separation between the extremely short core-state lifetime and the (comparably longer) electronic-state transfer and nuclear vibrational motion. This work is a natural extension of Segatta et al. (J. Chem. Theory Comput. 2023, 19, 2075-2091), in which some of the present authors coupled MCTDH quantum dynamics to spectroscopy simulation at different levels of sophistication. Full quantum dynamics and approximate expressions are compared by simulating X-ray transient absorption spectroscopy at the carbon K-edge in the pyrene molecule.
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Affiliation(s)
- Francesco Segatta
- Dipartimento
di Chimica Industriale “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Daniel Aranda
- ICMol, Universidad de Valencia, c/Catedrático José
Beltrán,
2, 46980 Paterna, Spain
- Istituto
di Chimica dei Composti Organometallici (ICCOM-CNR), Area della Ricerca del CNR, Via
Moruzzi 1, I-56124 Pisa, Italy
| | - Flavia Aleotti
- Dipartimento
di Chimica Industriale “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Francesco Montorsi
- Dipartimento
di Chimica Industriale “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Shaul Mukamel
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, 92697 California, United States
| | - Marco Garavelli
- Dipartimento
di Chimica Industriale “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Fabrizio Santoro
- Istituto
di Chimica dei Composti Organometallici (ICCOM-CNR), Area della Ricerca del CNR, Via
Moruzzi 1, I-56124 Pisa, Italy
| | - Artur Nenov
- Dipartimento
di Chimica Industriale “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
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Fu Z, Onishi H. Infrared and Near-Infrared Spectrometry of Anatase and Rutile Particles Bandgap Excited in Liquid. J Phys Chem B 2023; 127:321-327. [PMID: 36542796 PMCID: PMC9841978 DOI: 10.1021/acs.jpcb.2c07433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/02/2022] [Indexed: 12/24/2022]
Abstract
Chemical conversion of materials is completed in milliseconds or seconds by assembling atoms over semiconductor photocatalysts. Bandgap-excited electrons and holes reactive on this time scale are key to efficient atom assembly to yield the desired products. In this study, attenuated total reflection of infrared and near-infrared light was applied to characterize and quantify the electronic absorption of TiO2 photocatalysts excited in liquid. Nanoparticles of rutile or anatase were placed on a diamond prism, covered with liquid, and irradiated by steady UV light through the prism. Electrons excited in rutile particles (JRC-TIO-6) formed small polarons characterized by a symmetric absorption band spread over 10000-700 cm-1 with a maximum at 6000 cm-1. Electrons in anatase particles (JRC-TIO-7) created large polarons and produced an asymmetric absorption band that gradually strengthened at wavenumbers below 5000 cm-1 and sharply weakened at 1000 cm-1. The absorption spectrum of large electron polarons in TIO-7 was compared with the absorption reported in a Sr-doped NaTaO3 photocatalyst, and it was suggested that excited electrons were accommodated as large polarons in NaTaO3 photocatalysts efficient for artificial photosynthesis. UV-light power dependence of the absorption bands was observed in N2-exposed decane liquid to deduce electron-hole recombination kinetics. With light power density P > 200 W m-2 (TIO-6) and 2000 W m-2 (TIO-7), the polaron absorptions were enhanced with absorbance being proportional to P1/2. The observed 1/2-order power law suggested recombination of multiple electrons and holes randomly moving in each particle. Upon excitation with smaller P, the power-law order increased to unity. The unity-order power law was interpreted with recombination of an electron and a hole that were excited by the same photon. In addition, an average lifetime of 1 ms was estimated with electron polarons in TIO-6 when weakly excited at P = 20 W m-2 to simulate solar-light irradiation.
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Affiliation(s)
- Zhebin Fu
- Department
of Chemistry, School of Science, Kobe University, Kobe, Hyogo657-8501, Japan
| | - Hiroshi Onishi
- Department
of Chemistry, School of Science, Kobe University, Kobe, Hyogo657-8501, Japan
- Research
Center for Membrane and Film Technology, Kobe University, Kobe, Hyogo657-8501, Japan
- Division
of Advanced Molecular Science, Institute
for Molecular Science, Okazaki, Aichi444-8585, Japan
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Issa Hamoud H, Wolski L, Pankin I, Bañares MA, Daturi M, El-Roz M. In situ and Operando Spectroscopies in Photocatalysis: Powerful Techniques for a Better Understanding of the Performance and the Reaction Mechanism. Top Curr Chem (Cham) 2022; 380:37. [PMID: 35951125 DOI: 10.1007/s41061-022-00387-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/18/2022] [Indexed: 10/15/2022]
Abstract
In photocatalysis, a set of elemental steps are involved together at different timescales to govern the overall efficiency of the process. These steps are divided as follow: (1) photon absorption and excitation (in femtoseconds), (2) charge separation (femto- to picoseconds), (3) charge carrier diffusion/transport (nano- to microseconds), and (4 and 5) reactant activation/conversion and mass transfer (micro- to milliseconds). The identification and quantification of these steps, using the appropriate tool/technique, can provide the guidelines to emphasize the most influential key parameter that improve the overall efficiency and to develop the "photocatalyst by design" concept. In this review, the identification/quantification of reactant activation/conversion and mass transfer (steps 4 and 5) is discussed in details using the in situ/operando techniques, especially the infrared (IR), Raman, and X-ray absorption spectroscopy (XAS). The use of these techniques in photocatalysis was highlighted by the most recent and conclusive case studies which allow a better characterization of the active site and reveal the reaction pathways in order to establish a structure-performance relationship. In each case study, the reaction conditions and the reactor design for photocatalysis (pressure, temperature, concentration, etc.) were thoroughly discussed. In the last part, some examples in the use of time-resolved techniques (time-resolved FTIR, photoluminescence, and transient absorption) are also presented as an author's guideline to study the elemental steps in photocatalysis at shorter timescale (ps, ns, and µs).
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Affiliation(s)
- Houeida Issa Hamoud
- Laboratoire Catalyse et Spectrochimie, Normandie Université, ENSICAEN, UNICAEN, CNRS, 14050, Caen, France
| | - Lukasz Wolski
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Ilia Pankin
- Smart Materials, Research Institute, Southern Federal University, Sladkova Street 174/28, 344090, Rostov-on-Don, Russia
| | - Miguel A Bañares
- Catalytic Spectroscopy Laboratory, Instituto de Catalisis, ICP-CSIC, 28049, Madrid, Spain
| | - Marco Daturi
- Laboratoire Catalyse et Spectrochimie, Normandie Université, ENSICAEN, UNICAEN, CNRS, 14050, Caen, France
| | - Mohamad El-Roz
- Laboratoire Catalyse et Spectrochimie, Normandie Université, ENSICAEN, UNICAEN, CNRS, 14050, Caen, France.
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Ultrafast charge transfer dynamics in 2D covalent organic frameworks/Re-complex hybrid photocatalyst. Nat Commun 2022; 13:845. [PMID: 35149679 PMCID: PMC8837612 DOI: 10.1038/s41467-022-28409-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 01/18/2022] [Indexed: 12/16/2022] Open
Abstract
Rhenium(I)-carbonyl-diimine complexes have emerged as promising photocatalysts for carbon dioxide reduction with covalent organic frameworks recognized as perfect sensitizers and scaffold support. Such Re complexes/covalent organic frameworks hybrid catalysts have demonstrated high carbon dioxide reduction activities but with strong excitation energy-dependence. In this paper, we rationalize this behavior by the excitation energy-dependent pathways of internal photo-induced charge transfer studied via transient optical spectroscopies and time-dependent density-functional theory calculation. Under band-edge excitation, the excited electrons are quickly injected from covalent organic frameworks moiety into catalytic RheniumI center within picosecond but followed by fast backward geminate recombination. While under excitation with high-energy photon, the injected electrons are located at high-energy levels in RheniumI centers with longer lifetime. Besides those injected electrons to RheniumI center, there still remain some long-lived electrons in covalent organic frameworks moiety which is transferred back from RheniumI. This facilitates the two-electron reaction of carbon dioxide conversion to carbon monoxide. Re complexes within covalent organic frameworks have emerged as promising photocatalysts for CO2 reduction. Here, authors identify a high-energy electron transfer pathway during CO2 reduction that results in longer-lived excited states than a low-energy electron transfer pathway.
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Recent Advancements in the Understanding of the Surface Chemistry in TiO2 Photocatalysis. SURFACES 2020. [DOI: 10.3390/surfaces3010008] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Surface chemistry plays a major role in photocatalytic and photoelectrochemical processes taking place with the participation of TiO2. The synthesis methods, surface characterizations, theoretical research methods, and hardware over the last decade generated opportunities for progress in the surface science of this photocatalyst. Very recently, attention was paid to the design of photocatalysts at the nanoscale level by adjusting the types of exposed surfaces and their ratio, the composition and the surface structure of nanoparticles, and that of individual surfaces. The current theoretical methods provide highly detailed designs that can be embodied experimentally. The present review article describes the progress in the surface science of TiO2 and TiO2-based photocatalysts obtained over the last three years. Such aspects including the properties of macro- and nano-scale surfaces, noble-metal-loaded surfaces, doping with Mg and S, intrinsic defects (oxygen vacancies), adsorption, and photoreactions are considered. The main focus of the article is on the anatase phase of TiO2.
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