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miRNAs as key regulators via targeting the phytohormone signaling pathways during somatic embryogenesis of plants. 3 Biotech 2020; 10:495. [PMID: 33150121 DOI: 10.1007/s13205-020-02487-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/13/2020] [Indexed: 01/12/2023] Open
Abstract
Somatic embryogenesis is the regeneration of embryos from the somatic cell via dedifferentiation and redifferentiation without the occurrence of fertilization. A complex network of genes regulates the somatic embryogenesis process. Especially, microRNAs (miRNAs) have emerged as key regulators by affecting phytohormone biosynthesis, transport and signal transduction pathways. miRNAs are small, non-coding small RNA regulatory molecules involved in various developmental processes including somatic embryogenesis. Several types of miRNAs such as miR156, miR157, miR 159, miR 160, miR165, miR166, miR167, miR390, miR393 and miR396 have been reported to intricate in regulating somatic embryogenesis via targeting the phytohormone signaling pathways. Here we review current research progress on the miRNA-mediated regulation involved in somatic embryogenesis via regulating auxin, ethylene, abscisic acid and cytokinin signaling pathways. Further, we also discussed the possible role of other phytohormone signaling pathways such as gibberellins, jasmonates, nitric oxide, polyamines and brassinosteroids. Finally, we conclude by discussing the expression of miRNAs and their targets involved in somatic embryogenesis and possible regulatory mechanisms cross talk with phytohormones during somatic embryogenesis.
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2
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Schedlbauer J, Scherf U, Vogelsang J, Lupton JM. Dynamic Quenching of Triplet Excitons in Single Conjugated-Polymer Chains. J Phys Chem Lett 2020; 11:5192-5198. [PMID: 32506907 DOI: 10.1021/acs.jpclett.0c01308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
By measuring the fluorescence photon statistics of single chains of a conjugated polymer, we determine the lifetime of the metastable dark state, the triplet exciton. The single molecule emits single photons one at a time, giving rise to photon antibunching. These photons appear bunched in time over longer time scales because of excursions to the triplet dark state. Remarkably, this triplet intermittency in the fluorescence is spontaneously suppressed over time scales of seconds, implying that either triplet formation is inhibited or that triplets are selectively quenched without the singlet fluorescence being affected. Such discrete switching in the strength of photon bunching is only seen in highly ordered and rigid chains of a ladder-type conjugated polymer. It does not occur in single dye molecules. We propose that trapped photogenerated charges on the chain selectively quench triplets but not singlets, presumably because the effective diffusion length of triplets is longer along the highly rigid ladder-type backbone.
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Affiliation(s)
- Jakob Schedlbauer
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Ullrich Scherf
- Macromolecular Chemistry Group, Chemistry Department and Wuppertal Center for Smart Materials & Systems CM@S, Bergische Universität Wuppertal, Gauss-Strasse 20, 42097 Wuppertal, Germany
| | - Jan Vogelsang
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
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3
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Datko BD, Grey JK. Population dynamics of multiple triplet excitons revealed from time-dependent fluorescence quenching of single conjugated polymer chains. Sci Rep 2019; 9:817. [PMID: 30692627 PMCID: PMC6349865 DOI: 10.1038/s41598-018-37477-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/02/2018] [Indexed: 01/02/2023] Open
Abstract
The advent of multiple exciton harvesting schemes and prolonging exciton lifetimes to improve performance attributes of solar cells based on conjugated organic materials presents some interesting challenges that must be overcome in order to realize the full potential of these strategies. This is especially important for applications involving multi-chromophoric conjugated polymers where interactions between multiple spin-forbidden triplet excitons can be significant and are mediated by chain conformation. We use single molecule spectroscopic techniques to investigate interactions between multiple triplet excitons and emissive singlets by monitoring time-dependent fluorescence quenching on time scales commensurate with the triplet lifetime. Structurally related conjugated polymers differing by heteroatom substitution were targeted and we use a stochastic photodynamic model to numerically simulate the evolution of multi-exciton populations following photoexcitation. Single chains of poly(3-hexylthiophene) (P3HT) exhibit longer-lived triplet dynamics and larger steady-state triplet occupancies compared to those of poly(3-hexylselenophene) (P3HS), which has a larger reported triplet yield. Triplet populations evolve and relax much faster in P3HS which only becomes evident when considering all kinetic factors governing exciton population dynamics. Overall, we uncover new guidelines for effectively managing multi-exciton populations and interactions in conjugated polymers and improving their light harvesting efficiency.
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Affiliation(s)
- Benjamin D Datko
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - John K Grey
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM, 87131, USA.
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4
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How reduced excitonic coupling enhances light harvesting in the main photosynthetic antennae of diatoms. Proc Natl Acad Sci U S A 2017; 114:E11063-E11071. [PMID: 29229806 DOI: 10.1073/pnas.1714656115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Strong excitonic interactions are a key design strategy in photosynthetic light harvesting, expanding the spectral cross-section for light absorption and creating considerably faster and more robust excitation energy transfer. These molecular excitons are a direct result of exceptionally densely packed pigments in photosynthetic proteins. The main light-harvesting complexes of diatoms, known as fucoxanthin-chlorophyll proteins (FCPs), are an exception, displaying surprisingly weak excitonic coupling between their chlorophyll (Chl) a's, despite a high pigment density. Here, we show, using single-molecule spectroscopy, that the FCP complexes of Cyclotella meneghiniana switch frequently into stable, strongly emissive states shifted 4-10 nm toward the red. A few percent of isolated FCPa complexes and ∼20% of isolated FCPb complexes, on average, were observed to populate these previously unobserved states, percentages that agree with the steady-state fluorescence spectra of FCP ensembles. Thus, the complexes use their enhanced sensitivity to static disorder to increase their light-harvesting capability in a number of ways. A disordered exciton model based on the structure of the main plant light-harvesting complex explains the red-shifted emission by strong localization of the excitation energy on a single Chl a pigment in the terminal emitter domain due to very specific pigment orientations. We suggest that the specific construction of FCP gives the complex a unique strategy to ensure that its light-harvesting function remains robust in the fluctuating protein environment despite limited excitonic interactions.
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Yang P, Zhao J, Zhang L, Li L, Zhu Z. Intramolecular Hydrogen Bonds Quench Photoluminescence and Enhance Photocatalytic Activity of Carbon Nanodots. Chemistry 2015; 21:8561-8. [DOI: 10.1002/chem.201405088] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Indexed: 11/08/2022]
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6
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Krüger TPJ, Ilioaia C, Johnson MP, Belgio E, Horton P, Ruban AV, van Grondelle R. The specificity of controlled protein disorder in the photoprotection of plants. Biophys J 2014; 105:1018-26. [PMID: 23972853 DOI: 10.1016/j.bpj.2013.07.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 06/11/2013] [Accepted: 07/15/2013] [Indexed: 11/28/2022] Open
Abstract
Light-harvesting pigment-protein complexes of photosystem II of plants have a dual function: they efficiently use absorbed energy for photosynthesis at limiting sunlight intensity and dissipate the excess energy at saturating intensity for photoprotection. Recent single-molecule spectroscopy studies on the trimeric LHCII complex showed that environmental control of the intrinsic protein disorder could in principle explain the switch between their light-harvesting and photoprotective conformations in vivo. However, the validity of this proposal depends strongly on the specificity of the protein dynamics. Here, a similar study has been performed on the minor monomeric antenna complexes of photosystem II (CP29, CP26, and CP24). Despite their high structural homology, similar pigment content and organization compared to LHCII trimers, the environmental response of these proteins was found to be rather distinct. A much larger proportion of the minor antenna complexes were present in permanently weakly fluorescent states under most conditions used; however, unlike LHCII trimers the distribution of the single-molecule population between the strongly and weakly fluorescent states showed no significant sensitivity to low pH, zeaxanthin, or low detergent conditions. The results support a unique role for LHCII trimers in the regulation of light harvesting by controlled fluorescence blinking and suggest that any contribution of the minor antenna complexes to photoprotection would probably involve a distinct mechanism.
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Affiliation(s)
- Tjaart P J Krüger
- Department of Physics and Astronomy, VU University Amsterdam, Amsterdam, The Netherlands.
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7
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Das SK, Liu Y, Yeom S, Kim DY, Richards CI. Single-particle fluorescence intensity fluctuations of carbon nanodots. NANO LETTERS 2014; 14:620-5. [PMID: 24397573 DOI: 10.1021/nl403820m] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Fluorescent carbon nanodots (CNDs) were synthesized in oxidized and reduced forms and were analyzed at the single-particle level. Images of single CNDs at different excitation energies revealed significant heterogeneity in the lower energy trap sites between particles. We observed that a high percentage of reduced CND particles transitioned between multiple fluorescence intensity levels indicative of multichromophoric systems. Despite this behavior, individual CNDs exhibit single-step photobleaching and transient blinking to the background level suggesting single-molecule behavior.
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Affiliation(s)
- Somes K Das
- Department of Chemistry, University of Kentucky , 505 Rose Street, Lexington, Kentucky, United States
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8
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Zenkevich EI, von Borczyskowski C, Shulga AM. Structure and excited state properties of multiporphyrin arrays formed by supramolecular design. J PORPHYR PHTHALOCYA 2012. [DOI: 10.1142/s1088424603000914] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Structurally defined nanoscale self-assembled multiporphyrin arrays of variable geo-metry and composition (up to eight tetrapyrrole macrocycles) have been formed via two-fold extra-ligation in solutions at 77-293 K. The array formation is based on non-covalent binding interactions of the phenyl bridged Zn octaethylporphyrin chemical dimers or trimers, ( ZnOEP )2 Ph or ( ZnOEP )3 Ph 2, with di- and tetrapyridyl substituted tetrapyrrole extra-ligands (porphyrin, pentafluorophenyl substituted porphyrin, Cu porphyrin, tetrahydroporphyrin). Using steady-state and time-resolved measurements, spectral properties as well as pathways and dynamics of non-radiative relaxation processes (energy migration, photoinduced electron transfer, exchange d-π effects, realized in nano-femtosecond time scale) have been studied in these complexes upon variation of the composition, mutual geometry, redox and photophysical properties of interacting subunits as well as on the tempera-ture and polarity of surrounding.
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Affiliation(s)
- Eduard I. Zenkevich
- Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70 F. Skaryna Av., 220072 Minsk, Belarus
| | | | - Alexander M. Shulga
- Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70 F. Skaryna Av., 220072 Minsk, Belarus
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9
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Krüger TPJ, Ilioaia C, van Grondelle R. Fluorescence Intermittency from the Main Plant Light-Harvesting Complex: Resolving Shifts between Intensity Levels. J Phys Chem B 2011; 115:5071-82. [DOI: 10.1021/jp201609c] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tjaart P. J. Krüger
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Cristian Ilioaia
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Krüger TPJ, Ilioaia C, Valkunas L, van Grondelle R. Fluorescence Intermittency from the Main Plant Light-Harvesting Complex: Sensitivity to the Local Environment. J Phys Chem B 2011; 115:5083-95. [DOI: 10.1021/jp109833x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Tjaart P. J. Krüger
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Cristian Ilioaia
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Leonas Valkunas
- Institute of Physics, Center for Physical Sciences and Technology, Savanoriu 231, LT-02300 Vilnius, Lithuania and Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9, LT-10222 Vilnius, Lithuania
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Burrows SM, Patel P, Pappas D. Light tolerance of R-phycoerythrin and a tandem conjugate observed by single molecule recrossing events. APPLIED SPECTROSCOPY 2009; 63:709-715. [PMID: 19531299 DOI: 10.1366/000370209788559737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The recrossing of single molecules in a probe volume was used to investigate light harvesting and energy transfer between R-phycoerythrin (R-PE) and a tandem conjugate dye. The normalized recrossing ratio, Nr/Nt, was defined as the number of molecules that reenter the probe volume (Nr) to the total number of molecules detected (Nt). The energy transfer process in phycobiliproteins was studied as a function of excitation irradiation and irradiation time. This was achieved by investigating the average baseline-subtracted fluorescence intensity, normalized molecular recrossing ratio (Nr/Nt), and the number of molecules detected per second. The photon saturation irradiance of the R-PE and the tandem conjugate were compared with each other, showing that energy transfer to the tandem dye significantly improves photostability and light tolerance of the phycobiliprotein. The Nr/Nt ratio was used to study the photophysical properties of R-phycoerythrin and the tandem conjugate Streptavidin R-Phycoerythrin-AlexaFluor-647 (PE-647). Normalized molecular recrossings showed that energy transfer to a tandem conjugate could reduce the formation of triplet states in R-phycoerythrin and extend the light tolerance of certain phycobiliproteins.
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Affiliation(s)
- Sean M Burrows
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA
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12
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Walter MJ, Borys NJ, van Schooten KJ, Lupton JM. Light-harvesting action spectroscopy of single conjugated polymer nanowires. NANO LETTERS 2008; 8:3330-3335. [PMID: 18783280 DOI: 10.1021/nl801757p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We study exciton migration in single molecular nanowires, dye-endcapped multichromophoric conjugated polymers, as a function of excitation energy. This approach reveals the actual molecular absorption properties, uncovering the molecules within an ensemble and the chromophores within a molecule which contribute to absorption at a given wavelength. As the excitation energy is raised, an increasing number of polymers exhibit energy transfer suggesting that, in contrast to the emission spectrum, the absorption of a single chain under energy transfer conditions can be very broad even at 5 K. At the same time, the polarization anisotropy in excitation decreases due to an increase in the number of noncolinear chromophores involved in absorption. Power and wavelength-dependent measurements clearly discern the exciton blockade effect that gives rise to strong fluctuations of energy transfer. Although the polymer and endcap constitute nominally discrete spectroscopic entities, we are able to identify a subtle influence of the primary backbone exciton energy on the ultimate endcap emission. This demonstration of interchromophoric cooperativity provides a direct realization of how nonradiative energy dissipation in one nanoscale unit influences the spectroscopy of another.
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Affiliation(s)
- Manfred J Walter
- Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA
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13
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Burrows SM, Reif RD, Pappas D. Investigation of photobleaching and saturation of single molecules by fluorophore recrossing events. Anal Chim Acta 2007; 598:135-42. [PMID: 17693317 DOI: 10.1016/j.aca.2007.07.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 07/10/2007] [Accepted: 07/11/2007] [Indexed: 11/17/2022]
Abstract
A method for investigation of photobleaching and saturation of single molecules by fluorophore recrossing events in a laser beam is described. The diffraction-limited probe volumes encountered in single-molecule detection (SMD) produce high excitation irradiance, which can decrease available signal. The single molecules of several dyes were detected and the data was used to extract interpeak times above a defined threshold value. The interpeak times revealed the number of fluorophore recrossing events. The number of molecules detected that were within 2 ms of each other represented a molecular recrossing for this work. Calcein, fluorescein and R-phycoerythrin were analyzed and the saturation irradiance and photobleaching effects were determined as a function of irradiance. This approach is simple and it serves as a method of optimizing experimental conditions for single-molecule detection.
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Affiliation(s)
- Sean M Burrows
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, United States
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Forster M, Thomsson D, Hania PR, Scheblykin IG. Redistribution of emitting state population in conjugated polymers probed by single-molecule fluorescence polarization spectroscopy. Phys Chem Chem Phys 2007; 9:761-6. [PMID: 17268689 DOI: 10.1039/b615596k] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluctuations in the fluorescence polarization degree and direction are reported for the first time for single conjugated polymer molecules embedded in a polystyrene matrix at room temperature. The polymer molecule, a polythiophene derivative, clearly emits as a multi-chromophore ensemble showing that the energy does not funnel to any specific low-energy trap. The fluorescence instead originates from thermally populated exciton states with different relative orientations of the transition dipole moments. The fluctuations in the fluorescence polarization are explained in terms of changes in the relative contributions of the different exciton states to the signal due to conformational fluctuations of the molecule or selective exciton quenching by triplet states.
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Affiliation(s)
- M Forster
- Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden
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15
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Hania PR, Thomsson D, Scheblykin IG. Host Matrix Dependent Fluorescence Intensity Modulation by an Electric Field in Single Conjugated Polymer Chains. J Phys Chem B 2006; 110:25895-900. [PMID: 17181237 DOI: 10.1021/jp0653252] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An electric field oscillating at a frequency approximately 1 Hz is found to induce strong modulation of the fluorescence intensity of single poly[2-methoxy,5-(2'-ethyl-hexyloxy)-p-phenylene vinylene] (MEH-PPV) molecules (MW approximately 10(6)) embedded in a poly(methyl methacrylate) (PMMA) matrix. The MEH-PPV polymer chains are carefully isolated from the electrodes to avoid effects of injection. In a polystyrene matrix, fluorescence intensity modulations are on average much less pronounced. The difference in average modulation depth can be explained in terms of lower field-induced exciton dissociation rates in the MEH-PPV/polystyrene system compared to MEH-PPV/PMMA because of a lack of suitable acceptor sites. The observed electric field dependence of single-molecule fluorescence strongly suggests that energy transfer from singlet or even triplet excitons to long-living on-chain hole polarons contributes to the observed modulations. The observed large qualitative differences between the responses of different molecules probably reflect differences in chain topology and strongly anisotropic distributions of acceptor sites, while the hysteretic response of some molecules indicates conformational switching.
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Affiliation(s)
- P Ralph Hania
- Department of Chemical Physics, University of Lund, Box 124, SE-22100 Sweden
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16
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Herrmann A, Müllen K. From Industrial Colorants to Single Photon Sources and Biolabels: The Fascination and Function of Rylene Dyes. CHEM LETT 2006. [DOI: 10.1246/cl.2006.978] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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García-Parajó MF, Hernando J, Sanchez Mosteiro G, Hoogenboom JP, van Dijk EMHP, van Hulst NF. Energy transfer in single-molecule photonic wires. Chemphyschem 2006; 6:819-27. [PMID: 15884064 DOI: 10.1002/cphc.200400630] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Molecular photonics is a new emerging field of research around the premise that it is possible to develop optical devices using single molecules as building blocks. Truly technological impact in the field requires focussed efforts on designing functional molecular devices as well as having access to their photonic properties on an individual basis. In this Minireview we discuss our approach towards the design and single-molecule investigation of one-dimensional multimolecular arrays intended to work as molecular photonic wires. Three different schemes have been explored: a) perylene-based dimer and trimer arrays displaying coherent exciton delocalisation at room temperature; b) DNA-based unidirectional molecular wires containing up to five different chromophores and exhibiting weak excitonic interactions between neighbouring dyes; and c) one-dimensional multichromophoric polymers based on perylene polyisocyanides showing excimerlike emission. As a whole, our single-molecule data show the importance of well-defined close packing of chromophores for obtaining optimal excitonic behaviour at room temperature. Further improvement on (bio)chemical synthesis, together with the use of single-molecule techniques, should lead in the near future to efficient and reliable photonic wires with true device functionality.
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Affiliation(s)
- María F García-Parajó
- Applied Optics Group, Faculty of Science & Technology, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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18
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Lippitz M, Kulzer F, Orrit M. Statistical evaluation of single nano-object fluorescence. Chemphyschem 2006; 6:770-89. [PMID: 15884060 DOI: 10.1002/cphc.200400560] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Single nano-objects display strong fluctuations of their fluorescence signals. These random and irreproducible variations must be subject to statistical analysis to provide microscopic information. We review the main evaluation methods used so far by experimentalists in the field of single-molecule spectroscopy: time traces, correlation functions, distributions of "on" and "off" times, higher-order correlations. We compare their advantages and weaknesses from a theoretical point of view, illustrating our main conclusions with simple numerical simulations. We then review experiments on different types of single nano-objects, the phenomena which are observed and the statistical analyses applied to them.
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Affiliation(s)
- Markus Lippitz
- Molecular Nano-Optics and Spins, Huygens Laboratory, Leiden Institute of Physics (LION), Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
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19
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Ying L, Zhou D, Bruckbauer A. Comment on "trapping single molecules by dielectrophoresis". PHYSICAL REVIEW LETTERS 2006; 96:199801; author reply 199802. [PMID: 16803153 DOI: 10.1103/physrevlett.96.199801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Indexed: 05/10/2023]
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20
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Becker K, Lupton JM. Efficient Light Harvesting in Dye-Endcapped Conjugated Polymers Probed by Single Molecule Spectroscopy. J Am Chem Soc 2006; 128:6468-79. [PMID: 16683812 DOI: 10.1021/ja0609405] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of sophisticated microscopic models of energy transfer in linear multichromophoric systems such as conjugated polymers is rarely matched by suitable experimental studies on the microscopic level. To assess the roles of structural, temporal, and energetic disorder in energy transfer, single molecule spectroscopic investigations of the elementary processes leading to energetic relaxation in conjugated polymers are desirable. We present a detailed study of energy transfer processes occurring in dye-endcapped conjugated polymer molecules on the single molecule level. These processes are mostly masked in ensemble investigations. Highly efficient intramolecular energy transfer along a single polyindenofluorene chain to a perylene endcap occurs in many instances and is resolved in real time. We further consider the spectral emission characteristics of the single molecule, the polarization anisotropy which reveals the chain conformation, the fluorescence intermittency, and the temperature dependence and conclude that the efficiency of energy transfer in the ensemble is controlled by the statistics of the individual molecules. The weak thermal activation of energy transfer indicates the involvement of vibrational modes in interchromophoric coupling. Whereas backbone-endcap coupling is strong, the rate-limiting step for intramolecular energy transfer is the migration along the backbone. The results are particularly relevant to understanding undesired exciton trapping on fluorenone defects in polyfluorenes.
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Affiliation(s)
- Klaus Becker
- Photonics and Optoelectronics Group, Physics Department and CeNS, Ludwig-Maximilians-Universität, Amalienstrasse 54, 80799 München, Germany
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21
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Gaigalas A, Gallagher T, Cole KD, Singh T, Wang L, Zhang YZ. A Multistate Model for the Fluorescence Response of R-Phycoerythrin. Photochem Photobiol 2006; 82:635-44. [PMID: 16420100 DOI: 10.1562/2005-05-26-ra-544] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although strong fluorescence makes the R-phycoerythrin (R-PE) proteins increasingly useful in biological and clinical assays, they are subject to nonlinear effects including transitions to collective dark states and photodegradation, which complicate quantitative applications. We report measurements of R-PE fluorescence intensity as a function of incident power, duration of illumination and temperature. Emission intensity in the band at 570 nm is proportional to incident power for low power levels. At higher incident power, the emission at 570 nm is smaller than expected from a linear dependence on power. We propose that R-PE undergoes both reversible emission cessation on a millisecond time scale attributed to transitions to a collective dark state, and irreversible photodegradation on a time scale of minutes. Singlet oxygen scavengers such as dithiothreitol and n-propyl gallate have protective effects against the latter effect but not the former. Electrophoretic analysis of irradiated solutions of R-PE indicates that significant noncovalent aggregation is correlated with photodegradation. A multistate model based on fluorescence measurements and geometric analysis is proposed for the fluorophores in R-PE. The phycobilin fluorophores are partitioned into three groups: the phycourobilins (PUB) absorbing at 490 nm, one group of phycoerythobilins (PEB) absorbing at 530 nm (PEB-530) and another group of PEB absorbing at 560 nm (PEB-560). The two processes that result in the loss of fluorescence intensity are most likely associated with the PEB-560 group.
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Affiliation(s)
- A Gaigalas
- National Institute of Standards and Technology, Gaithersburg, MD, USA.
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22
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Tinnefeld P, Hofkens J, Herten DP, Masuo S, Vosch T, Cotlet M, Habuchi S, Müllen K, De Schryver FC, Sauer M. Higher-excited-state photophysical pathways in multichromophoric systems revealed by single-molecule fluorescence spectroscopy. Chemphyschem 2005; 5:1786-90. [PMID: 15580942 DOI: 10.1002/cphc.200400325] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Philip Tinnefeld
- Faculty of Physics, Applied Laser Physics and Laser Spectroscopy, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
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23
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Abstract
The development of nanotechnology using organic materials is one of the most intellectually and commercially exciting stories of our times. Advances in synthetic chemistry and in methods for the investigation and manipulation of individual molecules and small ensembles of molecules have produced major advances in the field of organic nanomaterials. The new insights into the optical and electronic properties of molecules obtained by means of single-molecule spectroscopy and scanning probe microscopy have spurred chemists to conceive and make novel molecular and supramolecular designs. Methods have also been sought to exploit the properties of these materials in optoelectronic devices, and prototypes and models for new nanoscale devices have been demonstrated. This Review aims to show how the interaction between synthetic chemistry and spectroscopy has driven the field of organic nanomaterials forward towards the ultimate goal of new technology.
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Affiliation(s)
- Andrew C Grimsdale
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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24
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25
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Szaciłowski K, Macyk W, Drzewiecka-Matuszek A, Brindell M, Stochel G. Bioinorganic photochemistry: frontiers and mechanisms. Chem Rev 2005; 105:2647-94. [PMID: 15941225 DOI: 10.1021/cr030707e] [Citation(s) in RCA: 561] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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26
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Gensch T, Böhmer M, Aramendía PF. Single Molecule Blinking and Photobleaching Separated by Wide-Field Fluorescence Microscopy. J Phys Chem A 2005; 109:6652-8. [PMID: 16834017 DOI: 10.1021/jp0510847] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Single molecule fluorescence detection of Atto590 in poly(vinyl alcohol) was achieved by using a wide-field epifluorescence microscope with CCD-camera detection. Image sequences are obtained from which the time traces of the detected molecules are built. We find a distinctive difference between the time evolution of the fluorescence originating from the molecules detected in the first image of the sequence compared to the time evolution of the fluorescence of the molecules detected in each image of the sequence. Atto590 shows very long blinking times and photobleaching and photoblinking that are both quadratically dependent on the irradiation power density. Our approach allows kinetic separation of photobleaching from blinking. The possibility of choosing different ensembles of molecules is demonstrated and taken advantage of for this aim. Initially dark molecules or low emitting ones that might be overlooked are important to describe the complete ensemble behavior.
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Affiliation(s)
- Thomas Gensch
- Institute for Biological Information Processing, IBI-1, Research Centre Jülich GmbH, 52425 Jülich, Germany.
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27
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De Schryver FC, Vosch T, Cotlet M, Van der Auweraer M, Müllen K, Hofkens J. Energy dissipation in multichromophoric single dendrimers. Acc Chem Res 2005; 38:514-22. [PMID: 16028885 DOI: 10.1021/ar040126r] [Citation(s) in RCA: 209] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Single-molecule spectroscopy of well-chosen dendritic multichromophoric systems allows investigation of fundamental photophysical processes such as energy or electron transfer in much greater detail than the respective ensemble measurements. In dendrimers with multiple chromophores, energy hopping and transfer to the chromophore with the energetically lowest S(1) state was observed. If more than one chromophore is in an excited state in one molecule, annihilation, either singlet-triplet or singlet-singlet, can occur. In the latter case, a higher singlet state is populated opening new deactivation pathways. In the presence of an electron donor, reversible electron transfer could be observed, and the rate constants of forward and backward electron transfer were established. The value of these rate constants fluctuates time-correlated with the rotational motion of the dendrimer arms and the mobility of the embedding matrix.
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Affiliation(s)
- F C De Schryver
- Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium.
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28
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Gesquiere AJ, Lee YJ, Yu J, Barbara PF. Single Molecule Modulation Spectroscopy of Conjugated Polymers. J Phys Chem B 2005; 109:12366-71. [PMID: 16852528 DOI: 10.1021/jp0507851] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper describes a new single molecule spectroscopy approach for the investigation of triplet-triplet and singlet-triplet interactions in conjugated polymers. The technique involves the irradiation of isolated single, mulitchromophoric, conjugated polymer molecules by a repetitive sequence of variable-intensity microsecond time scale excitation pulses. The fluorescence intensity is synchronously time-averaged for thousands of cycles of the pulse sequence to yield a high signal-to-noise fluorescence transient on the microsecond time scale. The transient can be analyzed with kinetic models to obtain quantitative information about the kinetics of triplet-triplet exciton annihilation and the quenching of singlet excitons by triplet excitons in conjugated polymers.
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Affiliation(s)
- Andre J Gesquiere
- Center for Nano- and Molecular Science and Technology and Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, USA
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29
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Yu J, Lammi R, Gesquiere AJ, Barbara PF. Singlet−Triplet and Triplet−Triplet Interactions in Conjugated Polymer Single Molecules. J Phys Chem B 2005; 109:10025-34. [PMID: 16852213 DOI: 10.1021/jp0506742] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Single molecule fluorescence correlation spectroscopy has been used to investigate the photodynamics of isolated single multichromophoric polymer chains of the conjugated polymers MEH-PPV and F8BT on the microsecond to millisecond time scale. The experimental results (and associated kinetic modeling) demonstrate that (i) triplet exciton pairs undergo efficient triplet-triplet annihilation on the <<30 micros time scale, (ii) triplet-triplet annihilation is the dominant mechanism for triplet decay at incident excitation powers > or =50 W/cm(2), and (iii) singlet excitons are quenched by triplet excitons with an efficiency on the order of (1)/(2). The high efficiency of this latter process ensures that single molecule fluorescence spectroscopy can be effectively used to indirectly monitor triplet exciton population dynamics in conjugated polymers. Finally, correlation spectroscopy of MEH-PPV molecules in a multilayer device environment reveals that triplet excitons are efficiently quenched by hole polarons.
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Affiliation(s)
- Ji Yu
- Center for Nano- and Molecular Science and Technology and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA
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30
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Tinnefeld P, Sauer M. Branching Out of Single‐Molecule Fluorescence Spectroscopy: Challenges for Chemistry and Influence on Biology. Angew Chem Int Ed Engl 2005; 44:2642-2671. [PMID: 15849689 DOI: 10.1002/anie.200300647] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the last decade emerging single-molecule fluorescence-spectroscopy tools have been developed and adapted to analyze individual molecules under various conditions. Single-molecule-sensitive optical techniques are now well established and help to increase our understanding of complex problems in different disciplines ranging from materials science to cell biology. Previous dreams, such as the monitoring of the motility and structural changes of single motor proteins in living cells or the detection of single-copy genes and the determination of their distance from polymerase molecules in transcription factories in the nucleus of a living cell, no longer constitute unsolvable problems. In this Review we demonstrate that single-molecule fluorescence spectroscopy has become an independent discipline capable of solving problems in molecular biology. We outline the challenges and future prospects for optical single-molecule techniques which can be used in combination with smart labeling strategies to yield quantitative three-dimensional information about the dynamic organization of living cells.
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Affiliation(s)
- Philip Tinnefeld
- Applied Laserphysics und Laserspectroscopy, Faculty of Physics, University of Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany, Fax: (+49) 521-106-2958
| | - Markus Sauer
- Applied Laserphysics und Laserspectroscopy, Faculty of Physics, University of Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany, Fax: (+49) 521-106-2958
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31
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Tinnefeld P, Sauer M. Neue Wege in der Einzelmolekül-Fluoreszenzspektroskopie: Herausforderungen für die Chemie und Einfluss auf die Biologie. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200300647] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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32
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Loos D, Cotlet M, De Schryver F, Habuchi S, Hofkens J. Single-molecule spectroscopy selectively probes donor and acceptor chromophores in the phycobiliprotein allophycocyanin. Biophys J 2005; 87:2598-608. [PMID: 15454454 PMCID: PMC1304678 DOI: 10.1529/biophysj.104.046219] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report on single-molecule fluorescence measurements performed on the phycobiliprotein allophycocyanin (APC). Our data support the presence of a unidirectional Förster-type energy transfer process involving spectrally different chromophores, alpha84 (donor) and beta84 (acceptor), as well as of energy hopping amongst beta84 chromophores. Single-molecule fluorescence spectra recorded from individual immobilized APC proteins indicate the presence of a red-emitting chromophore with emission peaking at 660 nm, which we connect with beta84, and a species with the emission peak blue shifted at 630 nm, which we attribute to alpha84. Polarization data from single APC trimers point to the presence of three consecutive red emitters, suggesting energy hopping amongst beta84 chromophores. Based on the single-molecule fluorescence spectra and assuming that emission at the ensemble level in solution comes mainly from the acceptor chromophore, we were able to resolve the individual absorption and emission spectra of the alpha84 and beta84 chromophores in APC.
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Affiliation(s)
- Davey Loos
- Laboratory of Photochemistry and Spectroscopy, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
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33
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Holman MW, Adams DM. Using Single-Molecule Fluorescence Spectroscopy to Study Electron Transfer. Chemphyschem 2004; 5:1831-6. [PMID: 15648130 DOI: 10.1002/cphc.200400123] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Techniques in single-molecule fluorescence spectroscopy now allow sophisticated studies of photophysical processes in single molecules. As interest grows in the possibilities of molecular electronics, researchers have begun to turn these techniques to the study of electron transfer. Electron-transfer reactions have now been detected and measured at the single-molecule level in a variety of systems and on a variety of timescales by adapting techniques from previous single-molecule fluorescence studies.
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Affiliation(s)
- Michael W Holman
- Department of Chemistry, Columbia University, New York, NY 10027, USA
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34
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Masuo S, Vosch T, Cotlet M, Tinnefeld P, Habuchi S, Bell TDM, Oesterling I, Beljonne D, Champagne B, Müllen K, Sauer M, Hofkens J, De Schryver FC. Multichromophoric Dendrimers as Single-Photon Sources: A Single-Molecule Study. J Phys Chem B 2004. [DOI: 10.1021/jp047804b] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sadahiro Masuo
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Tom Vosch
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Mircea Cotlet
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Philip Tinnefeld
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Satoshi Habuchi
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Toby D. M. Bell
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Ingo Oesterling
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - David Beljonne
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Benoît Champagne
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Klaus Müllen
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Markus Sauer
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Johan Hofkens
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
| | - Frans C. De Schryver
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Fakultät für Physik, Angewandte Laserphysik and Laserspektroskopie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, 20 Place du Parc, B-7000 Mons, Belgium, Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix (FUNDP), Rue de Bruxelles, 61, B-5000 Namur, Belgium, and Max
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Abstract
We review recent developments in single-molecule spectroscopy and microscopy. New optical methods provide access to the absorption, emission, or excitation spectra of single nano-objects and can determine either the positions of these objects with subwavelength accuracy or the full three-dimensional orientation of their transition dipole moments. Recent work aims at using single molecules as nanoparts or nanoelements in a variety of molecular-scale devices, from triggered sources of single photons to single-molecular switches. A prominent new direction explores the various interactions between molecules within individual multichromophoric systems obtained by chemical synthesis. These systems are the models for natural self-assembled systems such as the light-harvesting proteins of bacteria and green plants, which are currently studied on a single-molecule basis. Another important class of multichromophoric systems are conjugated polymers. The combination of microscopy with time- and frequency-resolved spectroscopy is opening a wide field of new and exciting applications to individual nano-objects.
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Affiliation(s)
- Florian Kulzer
- Molecular Nano-Optics and Spins (MoNOS), Huygens Laboratory, University of Leiden, 2333 CA Leiden, The Netherlands
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36
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Hofkens J, Cotlet M, Vosch T, Tinnefeld P, Weston KD, Ego C, Grimsdale A, Müllen K, Beljonne D, Brédas JL, Jordens S, Schweitzer G, Sauer M, De Schryver F. Revealing competitive Forster-type resonance energy-transfer pathways in single bichromophoric molecules. Proc Natl Acad Sci U S A 2003; 100:13146-51. [PMID: 14583594 PMCID: PMC263731 DOI: 10.1073/pnas.2235805100] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2003] [Indexed: 11/18/2022] Open
Abstract
We demonstrate measurements of the efficiency of competing Förster-type energy-transfer pathways in single bichromophoric systems by monitoring simultaneously the fluorescence intensity, fluorescence lifetime, and the number of independent emitters with time. Peryleneimide end-capped fluorene trimers, hexamers, and polymers with interchromophore distances of 3.4, 5.9, and on average 42 nm, respectively, served as bichromophoric systems. Because of different energy-transfer efficiencies, variations in the interchromophore distance enable the switching between homo-energy transfer (energy hopping), singlet-singlet annihilation, and singlet-triplet annihilation. The data suggest that similar energy-transfer pathways have to be considered in the analysis of single-molecule trajectories of donor/acceptor pairs as well as in natural and synthetic multichromophoric systems such as light-harvesting antennas, oligomeric fluorescent proteins, and dendrimers. Here we report selectively visualization of different energy-transfer pathways taking place between identical fluorophores in individual bichromophoric molecules.
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Affiliation(s)
- Johan Hofkens
- Laboratory for Photochemistry and Spectroscopy, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium.
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37
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Michalet X, Kapanidis AN, Laurence T, Pinaud F, Doose S, Pflughoefft M, Weiss S. The power and prospects of fluorescence microscopies and spectroscopies. ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 2003; 32:161-82. [PMID: 12598370 DOI: 10.1146/annurev.biophys.32.110601.142525] [Citation(s) in RCA: 180] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent years have witnessed a renaissance of fluorescence microscopy techniques and applications, from live-animal multiphoton confocal microscopy to single-molecule fluorescence spectroscopy and imaging in living cells. These achievements have been made possible not so much because of improvements in microscope design, but rather because of development of new detectors, accessible continuous wave and pulsed laser sources, sophisticated multiparameter analysis on one hand, and the development of new probes and labeling chemistries on the other. This review tracks the lineage of ideas and the evolution of thinking that have led to the actual developments, and presents a comprehensive overview of the field, with emphasis put on our laboratory's interest in single-molecule microscopy and spectroscopy.
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Affiliation(s)
- Xavier Michalet
- Department of Chemistry and Biochemistry, UCLA, Young Hall, 607 Charles E. Young Drive East, Los Angeles, California 90095, USA.
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38
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Vosch T, Cotlet M, Hofkens J, Van Der Biest K, Lor M, Weston K, Tinnefeld P, Sauer M, Latterini L, Müllen K, De Schryver FC. Probing Förster Type Energy Pathways in a First Generation Rigid Dendrimer Bearing Two Perylene Imide Chromophores. J Phys Chem A 2003. [DOI: 10.1021/jp034906d] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tom Vosch
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Mircea Cotlet
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Johan Hofkens
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Koen Van Der Biest
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Marc Lor
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Kenneth Weston
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Philip Tinnefeld
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Markus Sauer
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Loredana Latterini
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Klaus Müllen
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
| | - Frans C. De Schryver
- Contribution from the Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium, Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany, and Department of Chemistry, University of Perugia, Via Elce di Sotto, 8, I-06123 Perugia, Italy
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39
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Liu R, Holman MW, Zang L, Adams DM. Single-Molecule Spectroscopy of Intramolecular Electron Transfer in Donor-Bridge-Acceptor Systems. J Phys Chem A 2003. [DOI: 10.1021/jp034239o] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ruchuan Liu
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
| | - Michael W. Holman
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
| | - Ling Zang
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
| | - David M. Adams
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
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40
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Wang S, Luo H, Wang Y, Gong G. The effect of nanometer size of porous anodic aluminum oxide on adsorption and fluorescence of tetrahydroxyflavanol. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:1139-1144. [PMID: 12659881 DOI: 10.1016/s1386-1425(02)00314-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nanoporous anodic aluminum oxide, which was obtained by two-step electrochemical anodization aluminum process, showed strong physical adsorption capability of tetrahydroxyflavanol (THOF). The fluorescence peak of THOF was also dependent on its environment because the surrounding electron field affected the molecule luminescence in nanoporous alumina. The effect of nanometer size on adsorption and fluorescence of THOF is observed. The mechanism is primarily discussed.
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Affiliation(s)
- Sui Wang
- College of Chemistry and Chemical Engineering, Lanzhou University, 730000, Lanzhou, PR China
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41
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Scheblykin I, Zoriniants G, Hofkens J, De Feyter S, Van der Auweraer M, De Schryver FC. Photoluminescence intensity fluctuations and electric-field-induced photoluminescence quenching in individual nanoclusters of poly(phenylenevinylene). Chemphyschem 2003; 4:260-7. [PMID: 12674598 DOI: 10.1002/cphc.200390042] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Substantial fluctuations of the fluorescence intensity have been detected for single clusters of poly(phenylenevinylene) containing more than 75 polymer chains or 30,000 monomer units. To the best of our knowledge, this is the first time such fluctuations (which resemble the "blinking" effect in single-molecule fluorescence) have been reported for such a large molecular ensemble containing several macromolecules. Together with the distinct jumps, smooth fluctuations of the fluorescence intensity, with characteristic times from milliseconds to seconds, were observed. This fact distinguishes the fluorescence behaviour of the polymer clusters from that of other multichromophoric systems such as the single chains of conjugated polymers reported in the literature. The consecutive or simultaneous switching of one or several emitting sites from the "on" to "off" state does not explain the character of the fluctuations observed. We suggest that the quenching of the light-emitting exciton by a long-lived species, such as, for example, polarons, plays an important role in these unusual fluctuations. Electric field induced fluorescence quenching differs significantly for different clusters. It is proposed that this fluorescence was mainly quenched by polarons injected from the electrodes in the presence of an electric field. The specific behaviour of each cluster is explained by suggesting a different position of the clusters with respect to the electrodes.
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Affiliation(s)
- Ivan Scheblykin
- P.N. Lebedev Physics Institute, RAS, Leninsky pr. 53, 119991 GSP-1 Moscow, Russia
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42
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Jordens S, De Belder G, Lor M, Schweitzer G, Van der Auweraer M, Weil T, Reuther E, Müllen K, De Schryver FC. Energy transfer within perylene-terrylene dendrimers evidenced by polychromatic transient absorption measurements. Photochem Photobiol Sci 2003; 2:177-86. [PMID: 12713215 DOI: 10.1039/b210261g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The time dependent spectral properties of a first and a second generation dendrimer with peryleneimide chromophores at the rim and a terrylenediimide chromophore in the core were investigated by time resolved polychromatic transient absorption measurements. The obtained results of the dendritic structures were compared with those of three model compounds. In the perylene-terrylene dendrimers a very fast energy transfer process was observed. Besides energy transfer singlet-singlet annihilation could be observed. It could be concluded that competition between the rates of energy transfer and of singlet-singlet annihilation is dependent on the dendrimer generation.
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Affiliation(s)
- Sven Jordens
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium
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43
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44
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Tinnefeld P, Buschmann V, Weston KD, Sauer M. Direct Observation of Collective Blinking and Energy Transfer in a Bichromophoric System. J Phys Chem A 2003. [DOI: 10.1021/jp026565u] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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45
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Jordens S, De Belder G, Lor M, Schweitzer G, Van der Auweraer M, Weil T, Herrmann A, Wiesler UM, Müllen K, De Schryver FC. Generation dependent singlet–singlet annihilation within multichromophoric dendrimers studied by polychromatic transient absorption. Photochem Photobiol Sci 2003; 2:1118-24. [PMID: 14690223 DOI: 10.1039/b302501b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intramolecular kinetic processes in a series of shape-persistent meta- and para-substituted polyphenylene dendrimers bearing different peryleneimide chromophores at the rim have been investigated using time-resolved polychromatic transient absorption measurements. The influence of the generation number and different substitution patterns upon these processes was revealed by comparing different compounds. In particular, in multichromophoric systems a singlet-singlet annihilation process was detected. The corresponding time constant was dependent on the generation number.
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Affiliation(s)
- Sven Jordens
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium
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46
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Hernando J, van der Schaaf M, van Dijk EMHP, Sauer M, García-Parajó MF, van Hulst NF. Excitonic Behavior of Rhodamine Dimers: A Single-Molecule Study. J Phys Chem A 2002. [DOI: 10.1021/jp0218995] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jordi Hernando
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Martijn van der Schaaf
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Erik M. H. P. van Dijk
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Markus Sauer
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - María F. García-Parajó
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Niek F. van Hulst
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
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47
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Tinnefeld P, Weston KD, Vosch T, Cotlet M, Weil T, Hofkens J, Müllen K, De Schryver FC, Sauer M. Antibunching in the emission of a single tetrachromophoric dendritic system. J Am Chem Soc 2002; 124:14310-1. [PMID: 12452697 DOI: 10.1021/ja027343c] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photophysics of a dendrimer containing four chromophores are investigated at the single-molecule level. First, the multichromophoric character of single dendrimers' absorption is probed by modulating the linear polarization of the excitation beam. Subsequently, using circular polarization, the same dendrimers are excited, and their fluorescence transients are recorded. Using pulsed excitation in combination with the classical Hanbury-Brown and Twiss coincidence setup the presented data demonstrate that efficient singlet-singlet annihilation ensures that always only one photon is emitted even when several excitations are generated in an individual multichromophoric molecule.
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Affiliation(s)
- Philip Tinnefeld
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
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48
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Schweitzer G, Gronheid R, Jordens S, Lor M, De Belder G, Weil T, Reuther E, Müllen K, De Schryver FC. Intramolecular Directional Energy Transfer Processes in Dendrimers Containing Perylene and Terrylene Chromophores. J Phys Chem A 2002. [DOI: 10.1021/jp026459s] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gerd Schweitzer
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Roel Gronheid
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Sven Jordens
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Marc Lor
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Gino De Belder
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Tanja Weil
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Erik Reuther
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Klaus Müllen
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Frans C. De Schryver
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium, and Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
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49
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Gronheid R, Hofkens J, Köhn F, Weil T, Reuther E, Müllen K, De Schryver FC. Intramolecular Förster energy transfer in a dendritic system at the single molecule level. J Am Chem Soc 2002; 124:2418-9. [PMID: 11890773 DOI: 10.1021/ja017442a] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photophysics of a dendrimer containing four donor chromophores and one acceptor chromophore are studied at the single-molecule level. Upon excitation of the donors exclusive acceptor emission is observed due to efficient Förster energy transfer. For 70% of the molecules donor emission is observed after bleaching of the acceptor, leading to a reduction of the Förster energy transfer efficiency. Furthermore, we demonstrate that in this molecular system the donor chromophores do not bleach by a triplet-sensitized photooxidation.
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Affiliation(s)
- Roel Gronheid
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
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