Detection of Single Molecules Illuminated by a Light-Emitting Diode

Gerhardt, Ilja; Mai, Lijian; Lamas-Linares, Antı́a; Kurtsiefer, Christian

doi:10.3390/s110100905

Cited by 19 publications

(16 citation statements)

References 19 publications

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“…This contradicts the continuous absorption at short wavelengths for semiconductor nano-crystals 17 , 18 . Though it is not clear with limited number of data points, it seems the absorption spectrum is symmetric to the emission spectrum in the energy domain, and rapidly banishes at shorter wavelengths as a common feature of single molecules 19 , 20 . The average absorption cross-section values of five emitters at 532 nm and 594 nm are obtained as (4.3 ± 1.6) × 10 −16 cm 2 and (12.1 ± 6.0) × 10 −16 cm 2 , respectively.…”

Section: Resultsmentioning

confidence: 97%

Fluorescent impurity emitter in toluene and its photon emission properties

Trinh

Lee

2018

Sci Rep

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Single fluorescent emitters like colloidal quantum dots or single molecules are usually prepared in solutions and spin-coated onto cover glasses for studying. Toluene has been a widely used solvent in such studies. Here, we report on a fluorescent impurity emitter contained in toluene and its optical properties. The emission spectra of the single emitters show multiple peaks with the main peak varying from 2.03 eV (610 nm) to 2.14 eV (580 nm) and a red-shifted side peak with an average separation of 167 meV from the main peak. The emitted photons show a strong anti-bunching with a fluorescence lifetime of a few nanoseconds. They show very fast blinking behavior which cannot be properly detected by time-trajectory of photoluminescence intensity. An analysis based on the second-order correlation functions reveals that a three-level model can explain our measurements well and that the blinking transition time ranges only a few tens of microseconds. This single emitter in toluene is clearly distinguished from the fluorescent centers in the cover glass by their respective emission spectra. The single emitters in the cover glass also exhibit fast blinking behavior. These background emitters should be carefully identified and distinguished while studying the single fluorescent emitters.

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Section: Resultsmentioning

confidence: 97%

Fluorescent impurity emitter in toluene and its photon emission properties

Trinh

Lee

2018

Sci Rep

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“…Detection of single fluorescent molecules requires a dedicated microscopy setup with strong excitation power density from 100 to 5,000 W cm -2 due to the limited brightness of fluorescent dyes 1,2. The use of much lower excitation power would not only decrease photo-damage3,4 and auto-fluorescence background, but also enable utilization of inexpensive light sources5 important for high-throughput screening and diagnostics assays. Interestingly, fluorescent nanoparticles (NPs) that are many-fold brighter than single dyes can be detected even using a smartphone-based device 6.…”

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confidence: 99%

Giant light-harvesting nanoantenna for single-molecule detection in ambient light

et al. 2017

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Here, we explore the enhancement of single molecule emission by polymeric nano-antenna that can harvest energy from thousands of donor dyes to a single acceptor. In this nano-antenna, the cationic dyes are brought together in very close proximity using bulky counterions, thus enabling ultrafast diffusion of excitation energy (≤30 fs) with minimal losses. Our 60-nm nanoparticles containing >10,000 rhodamine-based donor dyes can efficiently transfer energy to 1-2 acceptors resulting in an antenna effect of ~1,000. Therefore, single Cy5-based acceptors become 25-fold brighter than quantum dots QD655. This unprecedented amplification of the acceptor dye emission enables observation of single molecules at illumination powers (1-10 mW cm-2) that are >10,000-fold lower than typically required in single-molecule measurements. Finally, using a basic setup, which includes a 20X air objective and a sCMOS camera, we could detect single Cy5 molecules by simply shining divergent light on the sample at powers equivalent to sunlight.

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“…A proper understanding of how light interacts with the moleculesubstrate interface is essential when designing technologically relevant materials for photonic applications. 1,2 These include optoelectronics, [3][4][5] photocatalysis, [6][7][8][9] bio/chemical sensing, [10][11][12][13][14][15][16][17][18] organic photovoltaics (OPVs), [19][20][21][22][23][24] and plasmonics. 1,5,18,[25][26][27] For example, molecule-surface coupling can modify both the energies and intensities of the single-particle spectra, electronic excitations, and phonons, thereby affecting the optical absorption of the molecule.…”

Section: Introductionmentioning

confidence: 99%

Tailoring a Molecule’s Optical Absorbance Using Surface Plasmonics

Mowbray

Despoja

2019

J. Phys. Chem. C

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Understanding the interaction of light with molecules physisorbed on substrates is a fundamental problem in photonics, with applications in biosensing, photovoltaics, photocatalysis, plasmonics, and nanotechnology. However, the design of novel functional materials in silico is severely hampered by the lack of robust and computationally efficient methods for describing both molecular absorbance and screening on substrates. Here we employ our hybrid G 0 [W 0 + ∆W]-BSE implementation, which incorporates the substrate via its screening ∆W at both the quasiparticle G 0 W 0 level and when solving the Bethe-Salpeter equation (BSE). We show this method can be used to both efficiently and accurately describe the absorption spectra of physisorbed molecules on metal substrates and thereby tailor the molecule's absorbance by altering the surface plasmon's energy. Specifically, we investigate how the optical absorption spectra of three prototypical π-conjugated molecules: benzene (C 6 H 6 ), terrylene (C 30 H 16 ) and fullerene (C 60 ), depends on the Wigner-Seitz radius r s of the metallic substrate. To gain further understanding of the light-molecule/substrate interaction, we also study the bright exciton's electron and hole densities and their interactions with infrared active vibrational modes. Our results show that (1) benzene's bright E 1 1u exciton at 7.0 eV, whose energy is insensitive to changes in r s , could be relevant for photocatalytic dehydrogenation and polymerization reactions, (2) terrylene's bright B 3u exciton at 2.3 eV hybridizes with the surface plasmon, allowing the tailoring of the excitonic energy and optical activation of a surface plasmon-like exciton, and (3) fullerene's π − π * bright and dark excitons at 6.4 and 6.8 eV hybridize with the surface plasmon, resulting in the tailoring of their excitonic energy and the activation of both a surface plasmon-like exciton and a dark quadrupolar mode via symmetry breaking by the substrate. This work demonstrates how a proper description of interfacial light-molecular/substrate interactions enables the prediction, design, and optimization of technologically relevant phenomena in silico. arXiv:1910.05434v1 [cond-mat.mes-hall]

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Detection of Single Molecules Illuminated by a Light-Emitting Diode

Cited by 19 publications

References 19 publications

Fluorescent impurity emitter in toluene and its photon emission properties

Fluorescent impurity emitter in toluene and its photon emission properties

Giant light-harvesting nanoantenna for single-molecule detection in ambient light

Tailoring a Molecule’s Optical Absorbance Using Surface Plasmonics

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