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Hetherington CV, Mohan T M N, Tilluck RW, Beck WF, Levine BG. Origin of Vibronic Coherences During Carrier Cooling in Colloidal Quantum Dots. J Phys Chem Lett 2023; 14:11651-11658. [PMID: 38109055 DOI: 10.1021/acs.jpclett.3c02384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Recent two-dimensional electronic spectroscopy experiments [Tilluck et al. J. Phys. Chem. Lett. 2021, 12 (39), 9677-9683] indicate the creation of coherent vibronic wavepackets in the first femtoseconds of hot carrier cooling in hexadecylamine-passivated CdSe quantum dots. Here we present a quantum chemical study of the origin of these coherences in a CdSe nanocrystal. We find that coherent wavepacket motions along vibrational coordinates with alkylamine character promote nonradiative relaxation through conical intersections between the exciton states of the inorganic core. Electronic excitations in the core are found to pass energy to the vibrations of the ligands via two distinct mechanisms: excitation of core phonon modes that are coupled to the ligand vibrations and direct excitation of ligand vibrations by delocalization of the exciton onto the ligands, both of which naturally arise within a photochemical framework based on many-electron potential energy surfaces. If these findings are demonstrated to be general, vibronic coherences may be leveraged to control photophysical outcomes in colloidal quantum dots.
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Affiliation(s)
- Caitlin V Hetherington
- Institute for Advanced Computational Science and Department of Chemistry, Stony Brook University Stony Brook, New York 11733 United States
| | - Nila Mohan T M
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 United States
| | - Ryan W Tilluck
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 United States
| | - Warren F Beck
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 United States
| | - Benjamin G Levine
- Institute for Advanced Computational Science and Department of Chemistry, Stony Brook University Stony Brook, New York 11733 United States
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2
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Hao Q, Lv H, Ma H, Tang X, Chen M. Development of Self-Assembly Methods on Quantum Dots. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1317. [PMID: 36770326 PMCID: PMC9919123 DOI: 10.3390/ma16031317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 01/28/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Quantum dot materials, with their unique photophysical properties, are promising zero-dimensional materials for encryption, display, solar cells, and biomedical applications. However, due to the large surface to volume ratio, they face the challenge of chemical instability and low carrier transport efficiency, which have greatly limited their reliability and utility. In light of the current development bottleneck of quantum dot materials, the chemical stability and physical properties can be effectively improved by the self-assembly method. This review will discuss the research progress of the self-assembly methods of quantum dots and analyze the advantages and disadvantages of those self-assembly methods. Furthermore, the scientific challenges and improvement in the self-assembly method of quantum dots are prospected.
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Affiliation(s)
- Qun Hao
- School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Hongyu Lv
- School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Haifei Ma
- School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Xin Tang
- School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, Beijing 100081, China
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314019, China
| | - Menglu Chen
- School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, Beijing 100081, China
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314019, China
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3
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Wang C, Orrison C, Son DH. Hot electrons generated from Mn‐doped quantum dots via upconversion for photocatalysis applications. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Chih‐Wei Wang
- Department of Chemistry Texas A&M University College Station Texas USA
| | - Connor Orrison
- Department of Chemistry Texas A&M University College Station Texas USA
| | - Dong Hee Son
- Department of Chemistry Texas A&M University College Station Texas USA
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4
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Papa CM, Garakyaraghi S, Granger DB, Anthony JE, Castellano FN. TIPS-pentacene triplet exciton generation on PbS quantum dots results from indirect sensitization. Chem Sci 2020; 11:5690-5696. [PMID: 32864083 PMCID: PMC7425078 DOI: 10.1039/d0sc00310g] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/18/2020] [Indexed: 01/06/2023] Open
Abstract
Many fundamental questions remain in the elucidation of energy migration mechanisms across the interface between semiconductor nanomaterials and molecular chromophores.
Many fundamental questions remain in the elucidation of energy migration mechanisms across the interface between semiconductor nanomaterials and molecular chromophores. The present transient absorption study focuses on PbS quantum dots (QDs) of variable size and band-edge exciton energy (ranging from 1.15 to 1.54 eV) post-synthetically modified with a carboxylic acid-functionalized TIPS-pentacene derivative (TPn) serving as the molecular triplet acceptor. In all instances, selective excitation of the PbS NCs at 743 nm leads to QD size-dependent formation of an intermediate with time constants ranging from 2–13 ps, uncorrelated to the PbS QD valence band potential. However, the rate constant for the delayed formation of the TPn triplet excited state markedly increases with increasing PbS conduction band energy, featuring a parabolic Marcus free energy dependence in the normal region. These observations provide evidence of an indirect triplet sensitization process being inconsistent with a concerted Dexter-like energy transfer process. The collective data are consistent with the generation of an intermediate resulting from hole trapping of the initial PbS excited state by midgap states, followed by formation of the TPn triplet excited state whose rate constant and yield increases with decreasing quantum dot size.
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Affiliation(s)
- Christopher M Papa
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695-8204 , USA .
| | - Sofia Garakyaraghi
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695-8204 , USA .
| | - Devin B Granger
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506-0055 , USA
| | - John E Anthony
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506-0055 , USA
| | - Felix N Castellano
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695-8204 , USA .
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5
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Abstract
After presenting the basic theoretical models of excitation energy transfer and charge transfer, I describe some of the novel experimental methods used to probe them. Finally, I discuss recent results concerning ultrafast energy and charge transfer in biological systems, in chemical systems and in photovoltaics based on sensitized transition metal oxides.
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Affiliation(s)
- Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC, Lausanne Centre for Ultrafast Science (LACUS), FSB, Station 6, CH-1015 Lausanne, Switzerland.
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6
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Wang HI, Infante I, Brinck ST, Cánovas E, Bonn M. Efficient Hot Electron Transfer in Quantum Dot-Sensitized Mesoporous Oxides at Room Temperature. NANO LETTERS 2018; 18:5111-5115. [PMID: 30039708 DOI: 10.1021/acs.nanolett.8b01981] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hot carrier cooling processes represent one of the major efficiency losses in solar energy conversion. Losses associated with cooling can in principle be circumvented if hot carrier extraction toward selective contacts is faster than hot carrier cooling in the absorber (in so-called hot carrier solar cells). Previous work has demonstrated the possibility of hot electron extraction in quantum dot (QD)-sensitized systems, in particular, at low temperatures. Here we demonstrate a room-temperature hot electron transfer (HET) with up to unity quantum efficiency in strongly coupled PbS quantum dot-sensitized mesoporous SnO2. We show that the HET efficiency is determined by a kinetic competition between HET rate ( KHET) and the thermalization rate ( KTH) in the dots. KHET can be modulated by changing the excitation photon energy; KTH can be modified through the lattice temperature. DFT calculations demonstrate that the HET rate and efficiency are primarily determined by the density of the state (DoS) of QD and oxide. Our results provide not only a new way to achieve efficient hot electron transfer at room temperature but also new insights on the mechanism of HET and the means to control it.
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Affiliation(s)
- Hai I Wang
- Max Planck Institute for Polymer Research , Ackermannweg 10 , Mainz 55128 , Germany
- Graduate School of Material Science in Mainz , University of Mainz , Staudingerweg 9 , Mainz 55128 , Germany
| | - Ivan Infante
- Department of Theoretical Chemistry, Faculty of Sciences , Vrije Universiteit Amsterdam , De Boelelaan 1083 , HV Amsterdam 1081 , The Netherlands
| | - Stephanie Ten Brinck
- Department of Theoretical Chemistry, Faculty of Sciences , Vrije Universiteit Amsterdam , De Boelelaan 1083 , HV Amsterdam 1081 , The Netherlands
| | - Enrique Cánovas
- Max Planck Institute for Polymer Research , Ackermannweg 10 , Mainz 55128 , Germany
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia) , Faraday 9 , Madrid 28049 , Spain
| | - Mischa Bonn
- Max Planck Institute for Polymer Research , Ackermannweg 10 , Mainz 55128 , Germany
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7
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Miao H, Wang Y, Yang X. Carbon dots derived from tobacco for visually distinguishing and detecting three kinds of tetracyclines. NANOSCALE 2018; 10:8139-8145. [PMID: 29675527 DOI: 10.1039/c8nr02405g] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Although a number of methods to perform assays of tetracyclines using fluorescent probes have been reported, approaches for discriminating and detecting tetracyclines are few. Herein, bright-blue fluorescent carbon dots (CDs) with a quantum yield (QY) of up to ∼27.9% were hydrothermally synthesized using tobacco as the carbon source. Importantly, the as-prepared carbon dots were employed as a fluorescent probe, enabling selective differentiation of three tetracyclines using a test strip and the related quantitative detection. Towards the mechanism, three kinds of tetracyclines showed different interactions with the CDs, leading to variations in their fluorescence emissions. To be specific, the fluorescence of CDs was quenched by tetracycline (TC) without a fluorescence shift (Em = 440 nm), which was caused by an inner filter effect rather than a change in the energy band gap. Moreover, the introduction of chlorotetracycline (CTC) resulted in a blue shift (Em = 415 nm) of the fluorescence of the CD; this phenomenon was induced by the enlarged energy band gap. The CDs also responded to oxytetracycline (OTC), and their corresponding fluorescence experienced a red shift (Em = 500 nm) due to the narrowed band gap. Consequently, a visual detection strategy for three tetracyclines has been proposed based on the quantitative evaluation of TC, OTC, and CTC concentrations in broad range from 6 × 10-6 to 4 × 10-9 M, 2 × 10-6 to 2 × 10-8 M, and 2 × 10-7 to 2 × 10-8 M, respectively. Moreover, we have successfully applied the current CDs for visually distinguishing the three tetracyclines on a test strip on the basis of CDs exhibiting three types of fluorescence (weak-blue, navy-blue, and chartreuse).
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Affiliation(s)
- Hong Miao
- College of Pharmaceutical Sciences, State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
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8
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Ren F, Lindley SA, Zhao H, Tan L, Gonfa BA, Pu YC, Yang F, Liu X, Vidal F, Zhang JZ, Vetrone F, Ma D. Towards understanding the unusual photoluminescence intensity variation of ultrasmall colloidal PbS quantum dots with the formation of a thin CdS shell. Phys Chem Chem Phys 2018; 18:31828-31835. [PMID: 27841403 DOI: 10.1039/c6cp05786a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this study, we report anomalous size-dependent photoluminescence (PL) intensity variation of PbS quantum dots (QDs) with the formation of a thin CdS shell via a microwave-assisted cation exchange approach. Thin shell formation has been established as an effective strategy for increasing the PL of QDs. Nonetheless, herein we observed an unusual PL decrease in ultrasmall QDs upon shell formation. We attempted to understand this abnormal phenomenon from the perspective of trap density variation and the probability of electrons and holes reaching surface defects. To this end, the quantum yield (QY) and PL lifetime (on the ns-μs time scales) of pristine PbS QDs and PbS/CdS core/shell QDs were measured and the radiative and non-radiative recombination rates were derived and compared. Moreover, transient absorption (TA) analysis (on the fs-ns time scale) was performed to better understand exciton dynamics at early times that lead to and affect longer time dynamics and optical properties such as PL. These experimental results, in conjunction with theoretical calculations of electron and hole wave functions, provide a complete picture of the photophysics governing the core/shell system. A model was proposed to explain the size-dependent optical and dynamic properties observed.
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Affiliation(s)
- Fuqiang Ren
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Sarah A Lindley
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA.
| | - Haiguang Zhao
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Long Tan
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Belete Atomsa Gonfa
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Ying-Chih Pu
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA.
| | - Fan Yang
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Xinyu Liu
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - François Vidal
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Jin Z Zhang
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA.
| | - Fiorenzo Vetrone
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada. and Centre for Self-Assembled Chemical Structures, McGill University, Montreal, Quebec H3A 2K6, Canada
| | - Dongling Ma
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
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9
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Dworak L, Roth S, Scheffer MP, Frangakis AS, Wachtveitl J. A thin CdSe shell boosts the electron transfer from CdTe quantum dots to methylene blue. NANOSCALE 2018; 10:2162-2169. [PMID: 29327031 DOI: 10.1039/c7nr08287h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
CdTe core and CdTe/CdSe core/shell quantum dots (QD) are investigated with steady state and time-resolved spectroscopic methods. The coating of the CdTe core with a 0.7 nm thick CdSe shell shifts the lowest exciton absorption band to the red by more than 70 nm making the CdTe/CdSe QD an interesting candidate for application in solar energy conversion. Femtosecond transient absorption measurements are applied to study the photoinduced electron transfer (ET) to the molecular acceptor methylene blue (MB). ET times after single excitation of the QD are determined for different MB : QD ratios. The ET reaction is significantly faster in the case of the MB-CdTe/CdSe QD complexes, indicative of an altered charge distribution in the photoexcited heterostructure with a higher electron density in the CdSe shell. As a result of the efficient absorption of incoming light and the faster ET reaction, the amount of reduced MB in the time resolved experiments is higher for CdTe/CdSe QD compared to CdTe QD.
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Affiliation(s)
- L Dworak
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, D-60438 Frankfurt am Main, Germany.
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10
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Ponseca CS, Chábera P, Uhlig J, Persson P, Sundström V. Ultrafast Electron Dynamics in Solar Energy Conversion. Chem Rev 2017; 117:10940-11024. [DOI: 10.1021/acs.chemrev.6b00807] [Citation(s) in RCA: 211] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Carlito S. Ponseca
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Pavel Chábera
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Jens Uhlig
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Petter Persson
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Villy Sundström
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
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11
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Wang HI, Bonn M, Cánovas E. Boosting Biexciton Collection Efficiency at Quantum Dot-Oxide Interfaces by Hole Localization at the Quantum Dot Shell. J Phys Chem Lett 2017; 8:2654-2658. [PMID: 28558226 DOI: 10.1021/acs.jpclett.7b00966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Harvesting multiexcitons from semiconductor quantum dots (QDs) has been proposed as a path toward photovoltaic efficiencies beyond the Shockley-Queisser limit. Although multiexciton generation efficiencies have been quantified extensively in QD structures, the challenge of actually collecting multiple excitons at electrodes-a prerequisite for high-efficiency solar cell devices-has received less attention. Here, we demonstrate that multiexciton collection (MEC) at the PbS QD/mesoporous SnO2 interface can be boosted 5-fold from ∼15 to reach ∼80% quantum yield, by partial localization of holes in a QD molecular capping shell. The resulting weakened Coulombic interactions give rise to reduced Auger recombination rates within the molecularly capped QDs, so that biexciton Auger relaxation, competing with MEC, is strongly suppressed. These results not only highlight the importance of surface chemistry and energetics at QD/ligand interfaces for multiexciton extraction but also provide clear design principles for realizing the benefits of MEG in sensitized systems exploited in solar cells and fuel geometries.
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Affiliation(s)
- Hai I Wang
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
- Graduate School of Material Science in Mainz, University of Mainz , Staudingerweg 9, 55128 Mainz, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
| | - Enrique Cánovas
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
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12
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Garakyaraghi S, Mongin C, Granger DB, Anthony JE, Castellano FN. Delayed Molecular Triplet Generation from Energized Lead Sulfide Quantum Dots. J Phys Chem Lett 2017; 8:1458-1463. [PMID: 28300410 DOI: 10.1021/acs.jpclett.7b00546] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The generation and transfer of triplet excitons across the molecular-semiconductor interface represents an important technological breakthrough featuring numerous fundamental scientific questions. This contribution demonstrates curious delayed formation of TIPS-pentacene molecular triplet excitons bound on the surface of PbS nanocrystals mediated through the initial production of a proposed charge transfer intermediate following selective excitation of the PbS quantum dots. Ultrafast UV-vis and near-IR transient absorption spectroscopy was used to track the dynamics of the initial PbS exciton quenching as well as time scale of the formation of molecular triplet excited states that persisted for 10 μs on the PbS surface, enabling subsequent energy and electron transfer reactivity. These results provide the pivotal proof-of-concept that PbS nanocrystals absorbing near-IR radiation can ultimately generate molecular triplets on their surfaces through processes distinct from direct Dexter triplet energy transfer. More broadly, this work establishes that small metal chalcogenide semiconductor nanocrystals interfaced with molecular chromophores exhibit behavior reminiscent of supramolecular chemical systems, a potentially impactful concept for nanoscience.
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Affiliation(s)
- Sofia Garakyaraghi
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Cédric Mongin
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Devin B Granger
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506-0055, United States
| | - John E Anthony
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506-0055, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
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13
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Miao H, Wang L, Zhuo Y, Zhou Z, Yang X. Label-free fluorimetric detection of CEA using carbon dots derived from tomato juice. Biosens Bioelectron 2016; 86:83-89. [DOI: 10.1016/j.bios.2016.06.043] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/13/2016] [Accepted: 06/14/2016] [Indexed: 11/17/2022]
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14
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Dong Y, Parobek D, Rossi D, Son DH. Photoemission of Energetic Hot Electrons Produced via Up-Conversion in Doped Quantum Dots. NANO LETTERS 2016; 16:7270-7275. [PMID: 27701861 DOI: 10.1021/acs.nanolett.6b03774] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The benefits of the hot electrons from semiconductor nanostructures in photocatalysis or photovoltaics result from their higher energy compared to that of the band-edge electrons facilitating the electron-transfer process. The production of high-energy hot electrons usually requires short-wavelength UV or intense multiphoton visible excitation. Here, we show that highly energetic hot electrons capable of above-threshold ionization are produced via exciton-to-hot-carrier up-conversion in Mn-doped quantum dots under weak band gap excitation (∼10 W/cm2) achievable with the concentrated solar radiation. The energy of hot electrons is as high as ∼0.4 eV above the vacuum level, much greater than those observed in other semiconductor or plasmonic metal nanostructures, which are capable of performing energetically and kinetically more-challenging electron transfer. Furthermore, the prospect of generating solvated electron is unique for the energetic hot electrons from up-conversion, which can open a new door for long-range electron transfer beyond short-range interfacial electron transfer.
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Affiliation(s)
- Yitong Dong
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
| | - David Parobek
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
| | - Daniel Rossi
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
| | - Dong Hee Son
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
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15
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Rezanejade Bardajee G, Hooshyar Z, Rezaei M, Khalili Khaneghah M, Fallahnejad F. Spectroscopic studies on the interactions of capped CdS quantum dots with human serum albumin (HSA) and bovine serum albumin (BSA). INORG NANO-MET CHEM 2016. [DOI: 10.1080/15533174.2016.1186098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
| | - Zari Hooshyar
- Department of Chemistry, Payame Noor University, Tehran, Iran
| | - Marzieh Rezaei
- Department of Chemistry, Payame Noor University, Tehran, Iran
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16
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Competition of branch-to-core exciton localization and interfacial electron transfer in CdSe tetrapods. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2015.08.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Wu K, Lian T. Quantum confined colloidal nanorod heterostructures for solar-to-fuel conversion. Chem Soc Rev 2016; 45:3781-810. [DOI: 10.1039/c5cs00472a] [Citation(s) in RCA: 202] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Colloidal one-dimensional (1D) semiconductor nanorods (NRs) offer the opportunity to simultaneously maintain quantum confinement in radial dimensions for tunable light absorptions and bulk like carrier transport in the axial direction for long-distance charge separations.
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Affiliation(s)
- Kaifeng Wu
- Department of Chemistry
- Emory University
- Atlanta
- USA
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18
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Yang Y, Gu J, Young JL, Miller EM, Turner JA, Neale NR, Beard MC. Semiconductor interfacial carrier dynamics via photoinduced electric fields. Science 2015; 350:1061-5. [DOI: 10.1126/science.aad3459] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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19
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Abstract
The two-photon photochemistry of CdSe quantum dots (QDs) has been systematically studied. We find that upon intense irradiation CdSe quantum dots that absorb two or more visible photons undergo photodarkening. The quantum yield for this process is on the order of 6% in chloroform and much smaller in nonpolar solvents, such as octane. An analysis of the energetics indicates that, following two-photon excitation, the biexciton undergoes an Auger process producing a hot hole. This hot hole is ejected to a surface-bound TOP ligand, forming a QD(-)/TOP(+) contact ion pair that separates in chloroform, but not in octane. The charged and deligated QD is dark, resulting in the overall photodarkening. This photodarkening reaction may or may not be reversible, depending on what other chemical components are in the irradiated solution. The quantum dot concentration dependence and PL decay kinetics indicate that charge recombination occurs rapidly, followed by ligand reattachment and reorganization on a longer (tens of minutes) time scale. The relation of this mechanism to one-photon photochemistry is also discussed.
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Affiliation(s)
- Youhong Zeng
- 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
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Dong Y, Choi J, Jeong HK, Son DH. Hot Electrons Generated from Doped Quantum Dots via Upconversion of Excitons to Hot Charge Carriers for Enhanced Photocatalysis. J Am Chem Soc 2015; 137:5549-54. [DOI: 10.1021/jacs.5b02026] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Yitong Dong
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Julius Choi
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Hae-Kwon Jeong
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Dong Hee Son
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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Long R, English NJ, Prezhdo OV. Minimizing Electron-Hole Recombination on TiO2 Sensitized with PbSe Quantum Dots: Time-Domain Ab Initio Analysis. J Phys Chem Lett 2014; 5:2941-6. [PMID: 26278240 DOI: 10.1021/jz5013627] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
TiO2 sensitized with quantum dots (QDs) gives efficient photovoltaic and photocatalytic systems due to high stability and large absorption cross sections of QDs and rapid photoinduced charge separation at the interface. The yields of the light-induced processes are limited by electron-hole recombination that also occurs at the interface. We combine ab initio nonadiabatic molecular dynamics with analytic theory to investigate the experimentally studied charge recombination at the PbSe QD-TiO2 interface. The time-domain atomistic simulation directly mimics the laser experiment and generates important details of the recombination mechanism. The process occurs due to coupling of the electronic subsystem to polar optical modes of the TiO2 surface. The inelastic electron-phonon scattering happens on a picosecond time scale, while the elastic scattering takes 40 fs. Counter to expectations, the donor-acceptor bonding strengthens at an elevated temperature. An analytic theory extends the simulation results to larger QDs and longer QD-TiO2 bridges. It shows that the electron-hole recombination rate decreases significantly for longer bridges and larger dots and that the main effect arises due to reduced donor-acceptor coupling rather than changes in the donor-acceptor energy gap. The study indicates that by varying QD size or ligands one can reduce charge losses while still maintaining efficient charge separation, providing design principles for optimizing solar cell design and increasing photon-to-electron conversion efficiencies.
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Affiliation(s)
- Run Long
- ‡Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089, United States
| | | | - Oleg V Prezhdo
- ‡Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089, United States
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