Optical Studies of Single Molecules at Room Temperature

Xie, Xiaohui; Trautman, J. K.

doi:10.1146/annurev.physchem.49.1.441

Cited by 641 publications

(560 citation statements)

References 83 publications

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“…The typical reversible blinking behavior on the timescale of seconds can be observed. 1,13,27 Jumps in PL intensity to less than half (or more than double) of its former value were observed 10 in approximately 25% of the recorded transients. These jumps are distributed arbitrarily in time and are caused by reversible photoinduced radical formation, or by subsequent irreversible photo-oxidation.…”

mentioning

confidence: 88%

Impact of charge carrier injection on single-chain photophysics of conjugated polymers

Hofmann

Vogelsang

Lupton

2016

Applied Physics Letters

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Charges in conjugated polymer materials have a strong impact on the photophysics and their interaction with the primary excited state species has to be taken into account in understanding device properties. Here, we employ single-molecule spectroscopy to unravel the influence of charges on several photoluminescence (PL) observables. The charges are injected either stochastically by a photochemical process, or deterministically in a hole-injection sandwich device configuration. We find that upon charge injection, besides a blue-shift of the PL emission and a shortening of the PL lifetime due to quenching and blocking of the lowest-energy chromophores, the non-classical photon arrival time distribution of the multichromophoric chain is modified towards a more classical distribution. Surprisingly, the fidelity of photon antibunching deteriorates upon charging, whereas one would actually expect the number of chromophores to be reduced. A qualitative model is presented to explain the observed PL changes. The results are of interest to developing a microscopic understanding of the intrinsic charge-exciton quenching interaction in devices.

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confidence: 88%

Impact of charge carrier injection on single-chain photophysics of conjugated polymers

Hofmann

Vogelsang

Lupton

2016

Applied Physics Letters

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“…If indeed the sole contribution to the acceptor bleaching was from a second blue photon, the acceptor emission rate would be determined by the population of , and exhibit a decay as a function of the pulse separation according to: (3) where τ A is the acceptor fluorescence lifetime, Δτ is the pulse separation, c and A are normalization factors. By fitting the acceptor emission response to pulse separation with this model we obtained τ A of 2.2 ns (Fig.…”

Section: Ensemble Measurements Of Bleaching Ratesmentioning

confidence: 99%

Photobleaching Pathways in Single-Molecule FRET Experiments

et al. 2007

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In order to acquire accurate structural and dynamical information on complex biomolecular machines using single-molecule fluorescence resonance energy transfer (sm-FRET), a large flux of donor and acceptor photons are needed. To achieve such fluxes one may use higher laser excitation intensity, however this induces increased rates of photobleaching. Anti-oxidants additives have been extensively used for reducing acceptor's photobleaching. Here we focus on deciphering the initial step along the photobleaching pathway. Utilizing an array of recently-developed single molecule and ensemble spectroscopies, and doubly-labeled Acyl-CoA binding protein and double-stranded DNA as model systems, we study these photobleaching pathways which place fundamental limitations on sm-FRET experiments. We find that: (i) acceptor photobleaching scales with FRET efficiency; (ii) acceptor photobleaching is enhanced under picosecond pulsed (vs. continuous wave) excitation; and (iii) acceptor photobleaching scales with the intensity of only the short wavelength (donor) excitation laser. We infer from these findings that the main pathway for acceptor's photobleaching is through absorption of a short wavelength photon from the acceptor's first excited singlet state and that donor's photobleaching is usually not a concern. We conclude by suggesting using short pulses for donor excitation, among other possible remedies, for reducing acceptor's photobleaching in sm-FRET measurements.

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“…The past decades have witnessed the development of several successful attempts in this regard, such as scanning near-field optical microscopy (SNOM) [1][2][3][4][5], single-molecule spectroscopy [6][7][8][9][10] and the combination of the two [11][12][13][14]. These efforts have however suffered from the mismatch between light and nanoscale matter, which leads to a small throughput between the input and output signals.…”

Section: Introductionmentioning

confidence: 99%

Light scattering under nanofocusing: Towards coherent nanoscopies

Mohammadi

Agio

2012

Optics Communications

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We investigate light scattering under nanofocusing in the context of coherent spectroscopy. We discuss the different mechanisms that may enhance the signal in extinction and how these depend on nanofocusing as well as on the probed system. We find that nanofocusing may improve the detection sensitivity by orders of magnitude under realistic conditions, enabling scanning implementations of coherent spectroscopy at the nanoscale.

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Optical Studies of Single Molecules at Room Temperature

Cited by 641 publications

References 83 publications

Impact of charge carrier injection on single-chain photophysics of conjugated polymers

Impact of charge carrier injection on single-chain photophysics of conjugated polymers

Photobleaching Pathways in Single-Molecule FRET Experiments

Light scattering under nanofocusing: Towards coherent nanoscopies

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