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Ye C, Zhang DS, Chen B, Tung CH, Wu LZ. Interfacial Charge Transfer Regulates Photoredox Catalysis. ACS CENTRAL SCIENCE 2024; 10:529-542. [PMID: 38559307 PMCID: PMC10979487 DOI: 10.1021/acscentsci.3c01561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 04/04/2024]
Abstract
Photoredox catalytic processes offer the potential for precise chemical reactions using light and materials. The central determinant is identified as interfacial charge transfer, which simultaneously engenders distinctive behavior in the overall reaction. An in-depth elucidation of the main mechanism and highlighting of the complexity of interfacial charge transfer can occur through both diffusive and direct transfer models, revealing its potential for sophisticated design in complex transformations. The fundamental photophysics uncover these comprehensive applications and offer a clue for future development. This research contributes to the growing body of knowledge on interfacial charge transfer in photoredox catalysis and sets the stage for further exploration of this fascinating area of research.
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Affiliation(s)
- Chen Ye
- Key
Laboratory of Photochemical Conversion and Optoelectronic Materials,
New Cornerstone Laboratory, Technical Institute
of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China
- School
of Future Technology, University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - De-Shan Zhang
- Key
Laboratory of Photochemical Conversion and Optoelectronic Materials,
New Cornerstone Laboratory, Technical Institute
of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China
- School
of Future Technology, University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - Bin Chen
- Key
Laboratory of Photochemical Conversion and Optoelectronic Materials,
New Cornerstone Laboratory, Technical Institute
of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China
- School
of Future Technology, University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - Chen-Ho Tung
- Key
Laboratory of Photochemical Conversion and Optoelectronic Materials,
New Cornerstone Laboratory, Technical Institute
of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China
- School
of Future Technology, University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
| | - Li-Zhu Wu
- Key
Laboratory of Photochemical Conversion and Optoelectronic Materials,
New Cornerstone Laboratory, Technical Institute
of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China
- School
of Future Technology, University of Chinese
Academy of Sciences, Beijing 100049, P. R. China
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2
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Sanchez MLK, Konecny SE, Narehood SM, Reijerse EJ, Lubitz W, Birrell JA, Dyer RB. The Laser-Induced Potential Jump: A Method for Rapid Electron Injection into Oxidoreductase Enzymes. J Phys Chem B 2020; 124:8750-8760. [PMID: 32924491 DOI: 10.1021/acs.jpcb.0c05718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxidoreductase enzymes often perform technologically useful chemical transformations using abundant metal cofactors with high efficiency under ambient conditions. The understanding of the catalytic mechanism of these enzymes is, however, highly dependent on the availability of well-characterized and optimized time-resolved analytical techniques. We have developed an approach for rapidly injecting electrons into a catalytic system using a photoactivated nanomaterial in combination with a range of redox mediators to produce a potential jump in solution, which then initiates turnover via electron transfer (ET) to the catalyst. The ET events at the nanomaterial-mediator-catalyst interfaces are, however, highly sensitive to the experimental conditions such as photon flux, relative concentrations of system components, and pH. Here, we present a systematic optimization of these experimental parameters for a specific catalytic system, namely, [FeFe] hydrogenase from Chlamydomonas reinhardtii (CrHydA1). The developed strategies can, however, be applied in the study of a wide variety of oxidoreductase enzymes. Our potential jump system consists of CdSe/CdS core-shell nanorods as a photosensitizer and a series of substituted bipyridinium salts as mediators with redox potentials in the range from -550 to -670 mV (vs SHE). With these components, we screened the effect of pH, mediator concentration, protein concentration, photosensitizer concentration, and photon flux on steady-state photoreduction and hydrogen production as well as ET and potential jump efficiency. By manipulating these experimental conditions, we show the potential of simple modifications to improve the tunability of the potential jump for application to study oxidoreductases.
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Affiliation(s)
- Monica L K Sanchez
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Sara E Konecny
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Sarah M Narehood
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Edward J Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - James A Birrell
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - R Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
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3
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Li H, Lu W, Song B, Zhou J, Zhao G, Han G. The design of Mn 2+&Co 2+ co-doped CdTe quantum dot sensitized solar cells with much higher efficiency. RSC Adv 2020; 10:35701-35708. [PMID: 35517066 PMCID: PMC9056921 DOI: 10.1039/d0ra06381a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/21/2020] [Indexed: 11/21/2022] Open
Abstract
High quality Mn2+-doped CdTe quantum dots (QDs), Co2+-doped CdTe QDs and Mn2+&Co2+ co-doped CdTe QDs were successfully synthesized via an aqueous phase method with mercaptopropanoic acid (MPA) ligands. The doped QDs maintain the same zinc blende structure of CdTe by X-ray diffraction (XRD). The Mn2+-doped CdTe QDs and Co2+-doped CdTe QDs both show a red-shift on absorption and photoluminescence (PL) spectra compared to pure CdTe QDs. In addition, Mn2+-doped CdTe QDs show a significant increase in the PL lifetime due to an orbitally forbidden d-d transition, which is of benefit to the reduction of electron recombination loss. Co2+ doping has a more matched doping energy level. In view of this, Mn2+&Co2+ co-doped CdTe QDs were applied as sensitizers for quantum dot sensitized solar cells, resulting in a significantly enhanced efficiency.
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Affiliation(s)
- Huazheng Li
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University Hangzhou 310027 P. R. China
| | - Wangwei Lu
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University Hangzhou 310027 P. R. China
| | - Bin Song
- State Key Laboratory of Silicon Materials & Department of Physics, Zhejiang University Hangzhou 310027 P. R. China
| | - Jing Zhou
- Department of Traffic Management Engineering, Zhejiang Police College Hangzhou 310053 P. R. China
| | - Gaoling Zhao
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University Hangzhou 310027 P. R. China
| | - Gaorong Han
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University Hangzhou 310027 P. R. China
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4
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Li Q, Lian T. Ultrafast Charge Separation in Two-Dimensional CsPbBr 3 Perovskite Nanoplatelets. J Phys Chem Lett 2019; 10:566-573. [PMID: 30642172 DOI: 10.1021/acs.jpclett.8b03610] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Two-dimensional (2D) cesium lead halide perovskite colloidal nanoplatelets show sharper excitonic absorption/emission peaks and larger absorption cross section in comparison to bulk materials and quantum dots. It remains unclear how 2D exciton and charge separation properties can be utilized to further enhance the performance of perovskite materials for optoelectrical applications. Herein, we report a study of exciton and interfacial charge-transfer dynamics of CsPbBr3 nanoplatelets via transient absorption spectroscopy. The exciton binding energy (∼260 meV) is determined via detailed spectral analysis. The exciton bleach is caused by band-edge exciton state-filling with negligible single carrier (electron or hole) contributions. Efficient charge separation can be achieved by selective electron and hole transfers to adsorbed molecular acceptors (benzoquinone and phenothiazine, respectively), and the half-life of the charge-separated state (≫100 ns) in nanoplatelet-phenothiazine complexes is >100 fold longer than that in quantum dot-phenothiazine complexes. Our results suggest that CsPbBr3 nanoplatelets are promising materials for photocatalysis and photovoltaic applications.
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Affiliation(s)
- Qiuyang Li
- Department of Chemistry , Emory University , 1515 Dickey Drive, NE , Atlanta , Georgia 30322 , United States
| | - Tianquan Lian
- Department of Chemistry , Emory University , 1515 Dickey Drive, NE , Atlanta , Georgia 30322 , United States
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5
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Wu H, Li X, Tung C, Wu L. Recent Advances in Sensitized Photocathodes: From Molecular Dyes to Semiconducting Quantum Dots. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1700684. [PMID: 29721417 PMCID: PMC5908380 DOI: 10.1002/advs.201700684] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/14/2017] [Indexed: 05/19/2023]
Abstract
The increasing demand for sustainable and environmentally benign energy has stimulated intense research to establish highly efficient photo-electrochemical (PEC) cells for direct solar-to-fuel conversion via water splitting. Light absorption, as the initial step of the catalytic process, is regarded as the foundation of establishing highly efficient PEC systems. To make full use of visible light, sensitization on photoelectrodes using either molecular dyes or semiconducting quantum dots provides a promising method. In this field, however, there remain many fundamental issues to be solved, which need in-depth study. Here, fundamental knowledge of PEC systems is introduced to enable readers a better understanding of this field. Then, the development history and current state in both molecular dye- and quantum dot-sensitized photocathodes for PEC water splitting are discussed. A systematical comparison between the two systems has been made. Special emphasis is placed on the research of quantum dot-sensitized photocathodes, which have shown superiority in both efficiency and durability towards PEC water splitting at the present stage. Finally, the opportunities and challenges in the future for sensitized PEC water-splitting systems are proposed.
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Affiliation(s)
- Hao‐Lin Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Xu‐Bing Li
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Chen‐Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Li‐Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
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6
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Grenland JJ, Maddux CJA, Kelley DF, Kelley AM. Charge Trapping versus Exciton Delocalization in CdSe Quantum Dots. J Phys Chem Lett 2017; 8:5113-5118. [PMID: 28972776 DOI: 10.1021/acs.jpclett.7b02242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The spectroscopic and photophysical similarities and differences between charge trapping by surface ligands on CdSe quantum dots and charge delocalization into the shell in excited CdSe core/shell nanocrystals are discussed. Optical absorption and resonance Raman spectroscopies are used to study small CdSe quantum dots coated with organic ligands that accept electrons (methyl viologen) or holes (phenothiazine, 4-methylbenzenethiol), as well as with semiconductor shells that delocalize electrons (CdS) or holes (CdTe). The organic ligands have only a small effect on the optical absorption spectrum and contribute negligibly to the resonance Raman spectra, indicating little participation of ligand orbitals in the initial excitation. The semiconductor shells more strongly red-shift the absorption spectrum by delocalizing the electron and/or hole into the shell, and vibrations of the shell appear in the resonance Raman spectrum, showing that the shell is involved in the vertical excitation. The qualitative differences between ligand and semiconductor shells are discussed in terms of the energetics and coupling strengths.
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Affiliation(s)
- Jamie J Grenland
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - Cassandra J A Maddux
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - David F Kelley
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - Anne Myers Kelley
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
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7
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Zang H, Routh PK, Meng Q, Cotlet M. Electron transfer dynamics from single near infrared emitting lead sulfide-cadmium sulfide nanocrystals to titanium dioxide. NANOSCALE 2017; 9:14664-14671. [PMID: 28937699 DOI: 10.1039/c7nr03500d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study we report the first successful demonstration of electron transfer between single near infrared emitting PbS/CdS nanocrystals and an external acceptor, titanium dioxide (TiO2). We demonstrate distance-dependent electron transfer from single nanocrystals to TiO2 and explore the effect of this process on the photoluminescence dynamics of these nanocrystals. Isolated PbS/CdS QDs are found to exhibit blinking dynamics similar to other nanocrystals like CdSe/ZnS; however, their photoluminescence follows a quasi two-state pattern with heterogeneous photoluminescence lifetimes which may be the result of their emission originating from different energy states. Electron transfer of these nanocrystals with an external acceptor inhibits their photoluminescence lifetime heterogeneity and biases their blinking dynamics in a manner similar to that observed for visible emitting CdSe/ZnS nanocrystals undergoing electron transfer with external acceptors. While the present study reconfirms the universality of quantum dot blinking among various types of nanocrystals, it also demonstrates that universality remains valid for the communication of various types of nanocrystals with the exterior world, here pictured as electron transfer with external acceptors.
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Affiliation(s)
- Huidong Zang
- Center for Functional Nanomaterials at Brookhaven National Laboratory, Upton, New York 11973, USA.
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8
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Debnath T, Sebastian D, Maiti S, Ghosh HN. Tuning Hole and Electron Transfer from Photoexcited CdSe Quantum Dots to Phenol Derivatives: Effect of Electron-Donating and -Withdrawing Moieties. Chemistry 2017; 23:7306-7314. [PMID: 28345273 DOI: 10.1002/chem.201700166] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Indexed: 11/09/2022]
Abstract
Charge-transfer processes from photoexcited CdSe quantum dots (QDs) to phenol derivatives with electron- donating (4-methoxy) and -withdrawing (4-nitro) moieties have been demonstrated by using steady-state and time- resolved emission and femtosecond transient absorption spectroscopy. Steady-state and time-resolved emission studies suggest that in the presence of both 4-nitrophenol (4NP) and 4-methoxyphenol (4MP) CdSe QDs luminescence is quenched. Stern-Volmer analysis suggests both static and dynamic mechanisms are active for both the QD/phenol composites. Cyclic voltammetric analysis recommends that photoexcited CdSe QDs can donate electrons to 4NP and holes to 4MP. To reconfirm both electron- and hole-transfer mechanisms, CdSe/CdS quasi-type II and CdSe/CdTe type II core-shell nanocrystals were synthesized and photoluminescence quenching was monitored in the absence and presence of both 4NP and 4MP, for which hole and electron transfer were systematically restricted. Results suggest that indeed electron and hole transfer take place from photoexcited CdSe to 4NP and 4MP, respectively. To monitor the charge-transfer dynamics in both systems on an early timescale, femtosecond transient absorption spectroscopic techniques have been employed. Electron and hole transfer and charge-recombination dynamics are discussed and the effect of electron-donating and -withdrawing groups has been demonstrated.
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Affiliation(s)
- Tushar Debnath
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India
| | - Deepa Sebastian
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India
| | - Sourav Maiti
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.,Department of Chemistry, Savitribai Phule Pune University, Pune, 411007, India
| | - Hirendra N Ghosh
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.,Institute of Nano Science and Technology, Mohali, Punjab, 160062, India
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9
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Harris RD, Bettis Homan S, Kodaimati M, He C, Nepomnyashchii AB, Swenson NK, Lian S, Calzada R, Weiss EA. Electronic Processes within Quantum Dot-Molecule Complexes. Chem Rev 2016; 116:12865-12919. [PMID: 27499491 DOI: 10.1021/acs.chemrev.6b00102] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The subject of this review is the colloidal quantum dot (QD) and specifically the interaction of the QD with proximate molecules. It covers various functions of these molecules, including (i) ligands for the QDs, coupled electronically or vibrationally to localized surface states or to the delocalized states of the QD core, (ii) energy or electron donors or acceptors for the QDs, and (iii) structural components of QD assemblies that dictate QD-QD or QD-molecule interactions. Research on interactions of ligands with colloidal QDs has revealed that ligands determine not only the excited state dynamics of the QD but also, in some cases, its ground state electronic structure. Specifically, the article discusses (i) measurement of the electronic structure of colloidal QDs and the influence of their surface chemistry, in particular, dipolar ligands and exciton-delocalizing ligands, on their electronic energies; (ii) the role of molecules in interfacial electron and energy transfer processes involving QDs, including electron-to-vibrational energy transfer and the use of the ligand shell of a QD as a semipermeable membrane that gates its redox activity; and (iii) a particular application of colloidal QDs, photoredox catalysis, which exploits the combination of the electronic structure of the QD core and the chemistry at its surface to use the energy of the QD excited state to drive chemical reactions.
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Affiliation(s)
- Rachel D Harris
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Stephanie Bettis Homan
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Mohamad Kodaimati
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Chen He
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | | | - Nathaniel K Swenson
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Shichen Lian
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Raul Calzada
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Emily A Weiss
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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10
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Kumar P, Kumar S, Ghosh S, Pal SK. Femtosecond insights into direct electron injection in dye anchored ZnO QDs following charge transfer excitation. Phys Chem Chem Phys 2016; 18:20672-81. [PMID: 27412034 DOI: 10.1039/c6cp01721e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The role of the charge transfer (CT) state in interfacial electron transfer in dye-sensitized semiconductor nanocrystals is still poorly understood. To address this problem, femtosecond transient absorption (TA) spectroscopy is used as a probe to investigate the electron injection across a newly synthesized coumarin dye (8-hydroxy-2-oxo-4-phenyl-2 benzo[h]chromene-3-carbonitrile, coded BC5) and ZnO quantum dots (QDs). Steady state and time-resolved spectroscopic measurements reveal that BC5 dye interacts strongly with ZnO QDs in the ground state forming a CT complex. The BC5-ZnO QD complex absorbs more towards red compared to only the dye and QDs, and emits fluorescence due to radiative recombination of photogenerated charges. The formation of charges following the excitation of the CT complex has been demonstrated by observing the signature of dye radical cations and electrons in the conduction band (CB) of the QDs in the TA spectra. The TA signals of these charges grow sharply as a result of ultrafast direct electron injection into the QD. We have monitored the complete dynamics of photogenerated charges by measuring the TA signals of the charges up to a couple of nanoseconds. The injected electrons that are free or shallowly trapped recombine with a time constant of 625 fs, whereas deeply trapped electrons disappear slowly (526 ps) via radiative recombination. Furthermore, theoretical studies based on ab initio calculations have been carried out to complement the experimental findings.
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Affiliation(s)
- Pushpendra Kumar
- School of Basic Sciences and Advanced Material Research Center, Indian Institute of Technology Mandi, Kamand 175005, H.P., India.
| | - Sunil Kumar
- School of Basic Sciences and Advanced Material Research Center, Indian Institute of Technology Mandi, Kamand 175005, H.P., India.
| | - Subrata Ghosh
- School of Basic Sciences and Advanced Material Research Center, Indian Institute of Technology Mandi, Kamand 175005, H.P., India.
| | - Suman Kalyan Pal
- School of Basic Sciences and Advanced Material Research Center, Indian Institute of Technology Mandi, Kamand 175005, H.P., India.
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11
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Secondary coordination sphere accelerates hole transfer for enhanced hydrogen photogeneration from [FeFe]-hydrogenase mimic and CdSe QDs in water. Sci Rep 2016; 6:29851. [PMID: 27417065 PMCID: PMC4945928 DOI: 10.1038/srep29851] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/24/2016] [Indexed: 11/22/2022] Open
Abstract
Achieving highly efficient hydrogen (H2) evolution via artificial photosynthesis is a great ambition pursued by scientists in recent decades because H2 has high specific enthalpy of combustion and benign combustion product. [FeFe]-Hydrogenase ([FeFe]-H2ase) mimics have been demonstrated to be promising catalysts for H2 photoproduction. However, the efficient photocatalytic H2 generation system, consisting of PAA-g-Fe2S2, CdSe QDs and H2A, suffered from low stability, probably due to the hole accumulation induced photooxidation of CdSe QDs and the subsequent crash of [FeFe]-H2ase mimics. In this work, we take advantage of supramolecular interaction for the first time to construct the secondary coordination sphere of electron donors (HA−) to CdSe QDs. The generated secondary coordination sphere helps realize much faster hole removal with a ~30-fold increase, thus leading to higher stability and activity for H2 evolution. The unique photocatalytic H2 evolution system features a great increase of turnover number to 83600, which is the highest one obtained so far for photocatalytic H2 production by using [FeFe]-H2ase mimics as catalysts.
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12
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Zeng P, Kirkwood N, Mulvaney P, Boldt K, Smith TA. Shell effects on hole-coupled electron transfer dynamics from CdSe/CdS quantum dots to methyl viologen. NANOSCALE 2016; 8:10380-10387. [PMID: 27139145 DOI: 10.1039/c6nr00168h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electron transfer (ET) dynamics from the 1Se electron state in quasi-type II CdSe/CdS core/shell quantum dots (QDs) to adsorbed methyl viologen (MV(2+)) were measured using femtosecond transient absorption spectroscopy. The intrinsic ET rate kET was determined from the measured average number of ET-active MV(2+) per QD, which permits reliable comparisons of variant shell thickness and different hole states. The 1Se electron was extracted efficiently from the CdSe core, even for CdS shells up to 20 Å thick. The ET rate decayed exponentially from 10(10) to 10(9) s(-1) for increasing CdS shell thicknesses with an attenuation factor β≈ 0.13 Å(-1). We observed that compared to the ground state exciton 1Se1S3/2 the electron coupled to the 2S3/2 hot hole state exhibited slower ET rates for thin CdS shells. We attribute this behaviour to an Auger-assisted ET process (AAET), which depends on electron-hole coupling controlled by the CdS shell thickness.
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Affiliation(s)
- Peng Zeng
- School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
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13
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Zang H, Routh PK, Huang Y, Chen JS, Sutter E, Sutter P, Cotlet M. Nonradiative Energy Transfer from Individual CdSe/ZnS Quantum Dots to Single-Layer and Few-Layer Tin Disulfide. ACS NANO 2016; 10:4790-4796. [PMID: 27031885 DOI: 10.1021/acsnano.6b01538] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The combination of zero-dimensional (0D) colloidal CdSe/ZnS quantum dots with tin disulfide (SnS2), a two-dimensional (2D)-layered metal dichalcogenide, results in 0D-2D hybrids with enhanced light absorption properties. These 0D-2D hybrids, when exposed to light, exhibit intrahybrid nonradiative energy transfer from photoexcited CdSe/ZnS quantum dots to SnS2. Using single nanocrystal spectroscopy, we find that the rate for energy transfer in 0D-2D hybrids increases with added number of SnS2 layers, a positive manifestation toward the potential functionality of such 2D-based hybrids in applications such as photovoltaics and photon sensing.
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Affiliation(s)
- Huidong Zang
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Prahlad K Routh
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
- Materials Science Department, Stony Brook University , Stony Brook, New York 11794, United States
| | - Yuan Huang
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Jia-Shiang Chen
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
- Materials Science Department, Stony Brook University , Stony Brook, New York 11794, United States
| | | | | | - Mircea Cotlet
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
- Materials Science Department, Stony Brook University , Stony Brook, New York 11794, United States
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14
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Li XB, Liu B, Wen M, Gao YJ, Wu HL, Huang MY, Li ZJ, Chen B, Tung CH, Wu LZ. Hole-Accepting-Ligand-Modified CdSe QDs for Dramatic Enhancement of Photocatalytic and Photoelectrochemical Hydrogen Evolution by Solar Energy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2016; 3:1500282. [PMID: 27774400 PMCID: PMC5063123 DOI: 10.1002/advs.201500282] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 10/16/2015] [Indexed: 05/21/2023]
Abstract
Solar H2 evolution of CdSe QDs can be significantly enhanced simply by introducing a suitable hole-accepting-ligand for achieving efficient hole extraction and transfer at the nanoscale interfaces, which opens an effective pathway for dissociation of excitons to generate long-lived charge separation, thus improving the solar-to-fuel conversion efficiency.
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Affiliation(s)
- Xu-Bing Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Bin Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Min Wen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Yu-Ji Gao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Hao-Lin Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Mao-Yong Huang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Zhi-Jun Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Bin Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Chen-Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Li-Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100190 P. R. China
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15
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Abstract
Understanding photoinduced charge transfer from nanomaterials is essential to the many applications of these materials. This review summarizes recent progress in understanding charge transfer from quantum dots (QDs), an ideal model system for investigating fundamental charge transfer properties of low-dimensional quantum-confined nanomaterials. We first discuss charge transfer from QDs to weakly coupled acceptors within the framework of Marcus nonadiabatic electron transfer (ET) theory, focusing on the dependence of ET rates on reorganization energy, electronic coupling, and driving force. Because of the strong electron-hole interaction, we show that ET from QDs should be described by the Auger-assisted ET model, which is significantly different from ET between molecules or from bulk semiconductor electrodes. For strongly quantum-confined QDs on semiconductor surfaces, the coupling can fall within the strong coupling limit, in which case the donor-acceptor interaction and ET properties can be described by the Newns-Anderson model of chemisorption. We also briefly discuss recent progress in controlling charge transfer properties in quantum-confined nanoheterostructures through wavefunction engineering and multiple exciton dissociation. Finally, we identify a few key areas for further research.
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Affiliation(s)
- Haiming Zhu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322;
| | - Ye Yang
- Department of Chemistry, Emory University, Atlanta, Georgia 30322;
| | - Kaifeng Wu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322;
| | - Tianquan Lian
- Department of Chemistry, Emory University, Atlanta, Georgia 30322;
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16
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Wu K, Du Y, Tang H, Chen Z, Lian T. Efficient Extraction of Trapped Holes from Colloidal CdS Nanorods. J Am Chem Soc 2015. [PMID: 26221916 DOI: 10.1021/jacs.5b04564] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cadmium Sulfide (CdS) nanostructures have been widely applied for solar driven H2 generations due to its suitable band gap and band edge energetics. For an efficient photoreduction reaction, hole scavenging from CdS needs to compete favorably with many recombination processes. Extensive spectroscopic studies show evidence for hole trapping in CdS nanostructures, which naturally leads the concern of extracting trapped holes from CdS in photocatalytic reactions. Here, we report a study of hole transfer dynamics from colloidal CdS nanorods (NRs) to adsorbed hole acceptor, phenothiazine (PTZ), using transient absorption spectroscopy. We show that >99% of the holes were trapped (with a time constant of 0.73 ps) in free CdS NRs to form a photoinduced transient absorption (PA) feature. In the presence of PTZ, we observed the decay of the PA feature and corresponding formation of oxidized PTZ(+) radicals, providing direct spectroscopic evidence for trapped hole transfer from CdS. The trapped holes were extracted by PTZ in 3.8 ± 1.7 ns (half-life) to form long-lived charge separated states (CdS(-)-PTZ(+)) with a half lifetime of 310 ± 50 ns. This hole transfer time is significantly faster than the slow conduction band electron-trapped hole recombination (half lifetime of 67 ± 1 ns) in free CdS NRs, leading to an extraction efficiency of 94.7 ± 9.0%. Our results show that despite rapid hole trapping in CdS NRs, efficient extraction of trapped holes by electron donors and slow recombination of the resulting charge-separated states can still be achieved to enable efficient photoreduction using CdS nanocrystals.
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Affiliation(s)
- Kaifeng Wu
- †Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - Yongling Du
- ‡College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Hua Tang
- †Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States.,§School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Zheyuan Chen
- †Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - Tianquan Lian
- †Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
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17
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Maity P, Debnath T, Chopra U, Ghosh HN. Cascading electron and hole transfer dynamics in a CdS/CdTe core-shell sensitized with bromo-pyrogallol red (Br-PGR): slow charge recombination in type II regime. NANOSCALE 2015; 7:2698-2707. [PMID: 25583154 DOI: 10.1039/c4nr05829a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ultrafast cascading hole and electron transfer dynamics have been demonstrated in a CdS/CdTe type II core-shell sensitized with Br-PGR using transient absorption spectroscopy and the charge recombination dynamics have been compared with those of CdS/Br-PGR composite materials. Steady state optical absorption studies suggest that Br-PGR forms strong charge transfer (CT) complexes with both the CdS QD and CdS/CdTe core-shell. Hole transfer from the photo-excited QD and QD core-shell to Br-PGR was confirmed by both steady state and time-resolved emission spectroscopy. Charge separation was also confirmed by detecting electrons in the conduction band of the QD and the cation radical of Br-PGR as measured from femtosecond transient absorption spectroscopy. Charge separation in the CdS/Br-PGR composite materials was found to take place in three different pathways, by transferring the photo-excited hole of CdS to Br-PGR, electron injection from the photo-excited Br-PGR to the CdS QD, and direct electron transfer from the HOMO of Br-PGR to the conduction band of the CdS QD. However, in the CdS/CdTe/Br-PGR system hole transfer from the photo-excited CdS to Br-PGR and electron injection from the photo-excited Br-PGR to CdS take place after cascading through the CdTe shell QD. Charge separation also takes place via direct electron transfer from the Br-PGR HOMO to the conduction band of CdS/CdTe. Charge recombination (CR) dynamics between the electron in the conduction band of the CdS QD and the Br-PGR cation radical were determined by monitoring the bleach recovery kinetics. The CR dynamics were found to be much slower in the CdS/CdTe/Br-PGR system than in the CdS/Br-PGR system. The formation of the strong CT complex and the separation of charges cascading through the CdTe shell help to slow down charge recombination in the type II regime.
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Affiliation(s)
- Partha Maity
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
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18
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Singhal P, Ghosh HN. Hot-Hole Extraction from Quantum Dot to Molecular Adsorbate. Chemistry 2015; 21:4405-12. [DOI: 10.1002/chem.201405947] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Indexed: 11/11/2022]
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19
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Yuan M, Voznyy O, Zhitomirsky D, Kanjanaboos P, Sargent EH. Synergistic doping of fullerene electron transport layer and colloidal quantum dot solids enhances solar cell performance. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:917-921. [PMID: 25504558 DOI: 10.1002/adma.201404411] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/03/2014] [Indexed: 06/04/2023]
Abstract
The spatial location of the predominant source of performance-limiting recombination in today's best colloidal quantum dot (CQD) cells is identified, pinpointing the TiO2:CQD junction; then, a highly n-doped PCBM layer is introduced at the CQD:TiO2 heterointerface. An n-doped PCBM layer is essential to maintain the depletion region and allow for efficient current extraction, thereby producing a record 8.9% in overall power conversion efficiency.
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Affiliation(s)
- Mingjian Yuan
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
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20
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Ding TX, Olshansky JH, Leone SR, Alivisatos AP. Efficiency of Hole Transfer from Photoexcited Quantum Dots to Covalently Linked Molecular Species. J Am Chem Soc 2015; 137:2021-9. [DOI: 10.1021/ja512278a] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Tina X. Ding
- Kavli Energy Nanosciences Institute, Berkeley, California 94720, United States
| | - Jacob H. Olshansky
- Kavli Energy Nanosciences Institute, Berkeley, California 94720, United States
| | | | - A. Paul Alivisatos
- Kavli Energy Nanosciences Institute, Berkeley, California 94720, United States
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21
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Algar WR, Stewart MH, Scott AM, Moon WJ, Medintz IL. Quantum dots as platforms for charge transfer-based biosensing: challenges and opportunities. J Mater Chem B 2014; 2:7816-7827. [DOI: 10.1039/c4tb00985a] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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22
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Debnath T, Maity P, Ghosh HN. Super Sensitization: Grand Charge (Hole/Electron) Separation in ATC Dye Sensitized CdSe, CdSe/ZnS Type-I, and CdSe/CdTe Type-II Core-Shell Quantum Dots. Chemistry 2014; 20:13305-13. [DOI: 10.1002/chem.201403267] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Indexed: 11/06/2022]
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23
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Debnath T, Maity P, Maiti S, Ghosh HN. Electron Trap to Electron Storage Center in Specially Aligned Mn-Doped CdSe d-Dot: A Step Forward in the Design of Higher Efficient Quantum-Dot Solar Cell. J Phys Chem Lett 2014; 5:2836-42. [PMID: 26278087 DOI: 10.1021/jz5012719] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Specially aligned surface-accumulated Mn-doped CdSe (MnCdSe) quantum dots (QDs) have been synthesized to study the effect of dopant atom on charge-carrier dynamics in QD materials. EPR studies suggest that the (4)T1 state of Mn(2+) lies above the conduction band of CdSe, and as a result no Mn-luminescence was observed from MnCdSe. Femtosecond transient absorption studies suggest that Mn atom introduces structural defects in surface-doped CdSe, which acts as electron trap center in doped QD for the photoexcited electron. Bromo-pyrogallol red (Br-PGR) were found to form strong charge-trasfer complex with both CdSe and MnCdSe QDs. Charge separation in both the CdSe/Br-PGR and MnCdSe/Br-PGR composites was found to take place in three different pathways by transferring the photoexcited hole of CdSe/MnCdSe QDs to Br-PGR, electron injection from photoexcited Br-PGR to the QDs, and direct electron transfer from the HOMO of Br-PGR to the conduction band of both the QDs. Hole-transfer dynamics are found to be quite similar (∼1.1 to 1.3 ps) for both of the systems and found to be independent of Mn doping. However, charge recombination dynamics was found to be much slower in the MnCdSe/Br-PGR system as compared with that in the CdSe/Br-PGR system, which confirms that the Mn dopant act as the electron storage center. As a consequence, the MnCdSe/Br-PGR system can be used as a better super sensitizer in quantum-dot-sensitized solar cell to increase efficiency further.
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24
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Kamat PV, Christians JA, Radich EJ. Quantum dot solar cells: hole transfer as a limiting factor in boosting the photoconversion efficiency. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:5716-5725. [PMID: 24669885 DOI: 10.1021/la500555w] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Semiconductor nanostructures are attractive for designing low-cost solar cells with tunable photoresponse. The recent advances in size- and shape-selective synthesis have enabled the design of quantum dot solar cells with photoconversion efficiencies greater than 5%. To make them competitive with other existing thin film or polycrystalline photovoltaic technologies, it is important to overcome kinetic barriers for charge transfer at semiconductor interfaces. This feature article focuses on the limitations imposed by slow hole transfer in improving solar cell performance and its role in the stability of metal chalcogenide solar cells. Strategies to improve the rate of hole transfer through surface-modified redox relays offer new opportunities to overcome the hole-transfer limitation. The mechanistic and kinetic aspects of hole transfer in quantum dot solar cells (QDSCs), nanowire solar cells (NWSCs), and extremely thin absorber (ETA) solar cells are discussed.
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Affiliation(s)
- Prashant V Kamat
- Radiation Laboratory and Department of Chemical & Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
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25
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Zhu H, Yang Y, Hyeon-Deuk K, Califano M, Song N, Wang Y, Zhang W, Prezhdo OV, Lian T. Auger-assisted electron transfer from photoexcited semiconductor quantum dots. NANO LETTERS 2014; 14:1263-1269. [PMID: 24359156 DOI: 10.1021/nl4041687] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Although quantum confined nanomaterials, such as quantum dots (QDs) have emerged as a new class of light harvesting and charge separation materials for solar energy conversion, theoretical models for describing photoinduced charge transfer from these materials remain unclear. In this paper, we show that the rate of photoinduced electron transfer from QDs (CdS, CdSe, and CdTe) to molecular acceptors (anthraquinone, methylviologen, and methylene blue) increases at decreasing QD size (and increasing driving force), showing a lack of Marcus inverted regime behavior over an apparent driving force range of ∼0-1.3 V. We account for this unusual driving force dependence by proposing an Auger-assisted electron transfer model in which the transfer of the electron can be coupled to the excitation of the hole, circumventing the unfavorable Franck-Condon overlap in the Marcus inverted regime. This model is supported by computational studies of electron transfer and trapping processes in model QD-acceptor complexes.
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Affiliation(s)
- Haiming Zhu
- Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States
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26
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ZANG HUIDONG, XU ZHIHUA, COTLET MIRCEA. CORE-SIZE DEPENDENT PHOTOLUMINESCENCE BLINKING OF ISOLATED QUANTUM DOT-FULLERENE HYBRIDS. ACTA ACUST UNITED AC 2014. [DOI: 10.1142/s1793048013500094] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We demonstrate the possibility to bias the photoluminescence blinking of isolated colloidal quantum dots coupled to fullerenes by varying the quantum dot core size. Changing the core size affects the energy offset between the donor and acceptor and directly affects the driving force for electron transfer between the two moieties. Single particle photoluminescence measurements reveal dramatic reduction in the on-time associated with the photoluminescence blinking in quantum dot-fullerene hybrids when the quantum dot core size decreases, a manifestation associated with enhanced electron transfer. [Formula: see text]Special Issue Comment: This project is about the blink properties of QDs in the presence of electron acceptor moieties and it connects with two articles from this Special Issue involving treatments when solving single molecules.1,2
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Affiliation(s)
- HUIDONG ZANG
- Center for Functional Nanomaterials, Brookhaven National Laboratory, 735 Brookhaven Avenue, Upton, New York 11973, USA
| | - ZHIHUA XU
- Center for Functional Nanomaterials, Brookhaven National Laboratory, 735 Brookhaven Avenue, Upton, New York 11973, USA
| | - MIRCEA COTLET
- Center for Functional Nanomaterials, Brookhaven National Laboratory, 735 Brookhaven Avenue, Upton, New York 11973, USA
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27
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Cohn AW, Rinehart JD, Schimpf AM, Weaver AL, Gamelin DR. Size dependence of negative trion Auger recombination in photodoped CdSe nanocrystals. NANO LETTERS 2014; 14:353-8. [PMID: 24328385 DOI: 10.1021/nl4041675] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report a systematic investigation of the size dependence of negative trion (T(-)) Auger recombination rates in free-standing colloidal CdSe nanocrystals. Colloidal n-type CdSe nanocrystals of various radii have been prepared photochemically, and their trion decay dynamics have been measured using time-resolved photoluminescence spectroscopy. Trion Auger time constants spanning 3 orders of magnitude are observed, ranging from 57 ps (radius R = 1.4 nm) to 2.2 ns (R = 3.2 nm). The data reveal a substantially stronger size dependence than found for bi- or multiexciton Auger recombination in CdSe or other semiconductor nanocrystals, scaling in proportion to R(4.3).
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Affiliation(s)
- Alicia W Cohn
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
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28
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Liu J, Hill CM, Pan S, Liu H. Interfacial charge transfer events of BODIPY molecules: single molecule spectroelectrochemistry and substrate effects. Phys Chem Chem Phys 2014; 16:23150-6. [DOI: 10.1039/c4cp02950j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BODIPY dye single molecules on nanostructured substrates are studied with a single molecule spectroelectrochemistry technique to reveal the heterogeneous charge transfer mechanism.
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Affiliation(s)
- Jia Liu
- Department of Chemistry
- The University of Alabama
- Tuscaloosa, 35487-0336 USA
| | - Caleb M. Hill
- Department of Chemistry
- The University of Alabama
- Tuscaloosa, 35487-0336 USA
| | - Shanlin Pan
- Department of Chemistry
- The University of Alabama
- Tuscaloosa, 35487-0336 USA
| | - Haiying Liu
- Department of Chemistry
- Michigan Technological University
- Houghton, 49931 USA
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29
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Zang H, Routh PK, Alam R, Maye MM, Cotlet M. Core size dependent hole transfer from a photoexcited CdSe/ZnS quantum dot to a conductive polymer. Chem Commun (Camb) 2014; 50:5958-60. [DOI: 10.1039/c3cc47975g] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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30
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Liu Z, Zhu H, Song N, Lian T. Probing spatially dependent photoinduced charge transfer dynamics to TiO2 nanoparticles using single quantum dot modified atomic force microscopy tips. NANO LETTERS 2013; 13:5563-5569. [PMID: 24164058 DOI: 10.1021/nl403181k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Using single CdSe/CdS quantum dot (QD) functionalized atomic force microscopy (AFM) tips, we demonstrate that the spatial dependence of photoinduced electron transfer dynamics from the single QD to TiO2 nanoparticles can be controlled and probed with high spatial (subdiffraction-limited) and temporal (limited by fluorescence microscopy) resolutions. This finding suggests the feasibility of using electron donor or acceptor modified AFM tips for simultaneous high resolution imaging of morphology and photoinduced charge transfer dynamics in nanomaterials.
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Affiliation(s)
- Zheng Liu
- Department of Chemistry, Emory University , Atlanta, Georgia 30322 United States
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31
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Lee M, Park JE, Park C, Choi HC. Synthesis of a p-type semiconducting phenothiazine exfoliatable layered crystal. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:9967-9971. [PMID: 23883168 DOI: 10.1021/la401611v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Phenothiazine (PTZ) crystals are grown by a physical vapor transport method in a horizontal tube furnace. The resulting disk-type PTZ single crystals have a layered structure, which can be mechanically exfoliated into stacked individual layers to exhibit various colors depending on the thickness. The PTZ single-crystal field-effect transistor (FET) devices exhibit a p-type semiconducting property with 3.03 × 10(-6) S/cm electrical conductivity, 1.15 × 10(-4) cm(2)/(V s) carrier mobility, and a 10(4) on/off ratio.
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Affiliation(s)
- Minkyung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-Dong, Nam-Gu, Pohang 790-784, Korea
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32
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Wu K, Liu Z, Zhu H, Lian T. Exciton annihilation and dissociation dynamics in group II-V Cd3P2 quantum dots. J Phys Chem A 2013; 117:6362-72. [PMID: 23611312 DOI: 10.1021/jp402511m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Semiconductor quantum dots (QDs) have emerged as a new class of light harvesting materials for solar energy conversion due to their unique size-dependent properties. Most recent studies have focused on II-VI group (such as CdX, X = S, Se, and Te) QDs and lead salt (such as PbS, PbSe, and PbTe) QDs. In this paper, we investigate exciton dissociation and annihilation dynamics of Cd3P2 QDs, a low bulk band gap (0.55 eV) II-V group material, to explore their potential application as a light harvesting component for photoreduction systems. For Cd3P2 QDs with 1S exciton band at 650 nm, a long-lived single exciton state with lifetime of 259 ns and a high emission quantum yield of 65% were observed. In Cd3P2 QD-rhodamine B (RhB, an electron acceptor) complexes, excitons in QDs could be dissociated by ultrafast electron transfer to RhB (6.2 ps), and the charge separated state had a long lifetime (31 ns). Although the photoinduced electron transfer rate in QD-RhB complexes decreased with increasing QD size, electron transfer was observed in QDs with 1S exciton bands at wavelength as long as 1050 nm. Compared with CdSe and PbS, Cd3P2 QDs with both more strongly reducing excited states and broader absorption in the visible and near IR region can be readily achieved, making them potential photosensitizers for photodriven water or CO2 reduction reactions.
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Affiliation(s)
- Kaifeng Wu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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33
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Song N, Zhu H, Liu Z, Huang Z, Wu D, Lian T. Unraveling the exciton quenching mechanism of quantum dots on antimony-doped SnO₂ films by transient absorption and single dot fluorescence spectroscopy. ACS NANO 2013; 7:1599-1608. [PMID: 23281781 DOI: 10.1021/nn3054494] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Integrating quantum dots (QDs) into modern optoelectronic devices requires an understanding of how a transparent conducting substrate affects the properties of QDs, especially their excited-state dynamics. Here, the exciton quenching dynamics of core/multishell (CdSe/CdS(3ML)ZnCdS(2ML)ZnS(2ML)) quantum dots deposited on glass, tin oxide (SnO₂), and antimony (Sb)-doped tin oxide (ATO) films are studied by transient absorption and single QD fluorescence spectroscopic methods. By comparing ensemble-averaged fluorescence decay and transient absorption kinetics, we show that, for QDs on SnO₂, the exciton is quenched by electron transfer from the QD to SnO₂. At the QD-ATO interface, much faster exciton quenching rates are observed and attributed to fast Auger recombination in charged QDs formed by Fermi level equilibration between the QD and n-doped ATO. Single QDs on SnO₂ and ATO show similar blinking dynamics with correlated fluctuations of emission intensities and lifetimes. Compared to QDs on SnO₂, QDs on ATO films show larger variation of average exciton quenching rates, which is attributed to a broad distribution of the number of charges and nature of charging sites on the QD surface.
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Affiliation(s)
- Nianhui Song
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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34
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Opperwall SR, Divakaran A, Porter EG, Christians JA, Denhartigh AJ, Benson DE. Wide dynamic range sensing with single quantum dot biosensors. ACS NANO 2012; 6:8078-8086. [PMID: 22924857 DOI: 10.1021/nn303347k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Single-particle analysis of biosensors that use charge transfer as the means for analyte-dependent signaling with semiconductor nanoparticles, or quantum dots, was examined. Single-particle analysis of biosensors that use energy transfer show analyte-dependent switching of nanoparticle emission from off to on. The charge-transfer-based biosensors reported here show constant emission, where the analyte (maltose) increases the emission intensity. By monitoring the same nanoparticles under various conditions, a single charge-transfer-based biosensor construct (one maltose binding protein, one protein attachment position for the reductant, one type of nanoparticle) showed a dynamic range for analyte (maltose) detection spanning from 100 pM to 10 μM while the emission intensities increase from 25 to 175% at the single-particle level. Since these biosensors were immobilized, the correlation between the detected maltose concentration and the maltose-dependent emission intensity increase could be examined. Minimal correlation between maltose detection limits and emission increases was observed, suggesting a variety of reductant-nanoparticle surface interactions that control maltose-dependent emission intensity responses. Despite the heterogeneous responses, monitoring biosensor emission intensity over 5 min provided a quantifiable method to monitor maltose concentration. Immobilizing and tracking these biosensors with heterogeneous responses, however, expanded the analyte-dependent emission intensity and the analyte dynamic range obtained from a single construct. Given the wide dynamic range and constant emission of charge-transfer-based biosensors, applying these single molecule techniques could provide ultrasensitive, real-time detection of small molecules in living cells.
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Affiliation(s)
- Stacey R Opperwall
- Department of Chemistry & Biochemisty, Calvin College, 1726 Knollcrest Circle SE, Grand Rapids, Michigan 49546, United States
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35
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Zhu H, Lian T. Enhanced Multiple Exciton Dissociation from CdSe Quantum Rods: The Effect of Nanocrystal Shape. J Am Chem Soc 2012; 134:11289-97. [DOI: 10.1021/ja304724u] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Haiming Zhu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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