Spectral tuning of the phosphorescence from metalloporphyrins attached to gold nanorods

Djiango, Martin; Ritter, Kathrin; Müller, R.; Klar, Thomas A.

doi:10.1364/oe.20.019374

Cited by 7 publications

(6 citation statements)

References 48 publications

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“…Additionally, quenching of luminescence depends on the particle size and shape in the case of porphyrin attachment to gold nanoparticles [40]. The position of the porphyrin fluorescence peak can be affected by combination with noble metals [41,42]. In [43], an attachment of porphyrin to gold clusters through a molecular spacer was reported resulting in suppression of the quenching of the porphyrin excited singlet, as compared to the quenching of self-assembled porphyrins on a two-dimensional flat gold surface.…”

Section: Discussionmentioning

confidence: 99%

Surface morphology and optical properties of porphyrin/Au and Au/porphyrin/Au systems

et al. 2013

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Porphyrin/Au and Au/porphyrin/Au systems were prepared by vacuum evaporation and vacuum sputtering onto glass substrate. The surface morphology of as-prepared systems and those subjected to annealing at 160°C was studied by optical microscopy, atomic force microscopy, and scanning electron microscopy techniques. Absorption and luminescence spectra of as-prepared and annealed samples were measured. Annealing leads to disintegration of the initially continuous gold layer and formation of gold nanoclusters. An amplification of Soret band magnitude was observed on the Au/meso-tetraphenyl porphyrin (TPP) system in comparison with mere TPP. Additional enhancement of luminescence was observed after the sample annealing. In the case of sandwich Au/porphyrin/Au structure, suppression of one of the two porphyrins’ luminescence maxima and sufficient enhancement of the second one were observed.

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Section: Discussionmentioning

confidence: 99%

Surface morphology and optical properties of porphyrin/Au and Au/porphyrin/Au systems

et al. 2013

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“…Most of the studies reported to date on plasmon-enhanced fluorescence of porphyrins, or related compounds, focus on multichromophore systems. These include studies on core–shell assemblies composed of metal nanoparticles coated by a layer of porphyrins directly linked to its surface or entrapped in a silica layer. − From a different perspective, plasmon-enhanced fluorescence has also been studied on light-harvesting complexes from natural systems that instead of porphyrins comprise chlorophyll pigments. − The collective behavior of the multiple chromophores in these systems, such as exciton coupling or energy transfer, bring additional complexity to the evaluation of antenna effects. Therefore, a clear evaluation of plasmon-enhanced fluorescence on individual chromophores would be desirable for a rational design of nanocomposite systems that incorporate porphyrins, and it would allow the assessment of the limits of emission enhancement on a weak emitting molecule.…”

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confidence: 99%

Extreme Enhancement of Single-Molecule Fluorescence from Porphyrins Induced by Gold Nanodimer Antennas

Francisco

Botequim

Prazeres

et al. 2019

J. Phys. Chem. Lett.

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Porphyrins are typically weak emitters, which presents challenges to their optical detection by single-molecule fluorescence microscopy. In this contribution, we explore the enhancement effect of gold nanodimer antennas on the fluorescence of porphyrins in order to enable their single-molecule optical detection. Four meso-substituted free-base porphyrins were evaluated: two cationic, one neutral, and one anionic porphyrin. The gold nanodimer antennas are able to enhance the emission from these porphyrins by a factor of 105–106 increase in the maximum detected photon rates. This extreme enhancement is due to the combination of an antenna effect on the excitation rate that is estimated to be above 104-fold and an emission efficiency that corresponds to an increase of 2–10 times in the porphyrin’s fluorescence quantum yield.

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“…Examples of enhanced ISC and phosphorescence can be found in the literature. − Unlike the short-range electron exchange, which is limited to a thin layer adjacent to the metal, the field effects extend for tens of nanometers and could modulate the ISC rate across the entire P3HT@AuNR sample. This is an appealing possibility; however, the acceleration of the ISC and phosphorescence is small, with the highest reported enhancement factor of 2.4, which is much too low to account for the formation of the P3HT triplet on a subpicosecond time scale. If such effects are present in P3HT@AuNR , they are of secondary importance.…”

Section: Resultsmentioning

confidence: 99%

Excited State Behavior of Single Strand and Bulk P3HT in Contact with a Au-Nanowire Array

et al. 2018

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Pump−probe transient absorption and single molecule fluorescence microscopy reveal multifaceted excited state behavior of regioregular (RR) P3HT interacting with a hexagonal array of Au nanowires. An average 5-fold increase of fluorescence intensity has been detected for single strands of P3HT in the presence of the nanowire array, with the strongest emitters exceeding the brightness of their counterparts on glass by a factor of 40. The single molecule trajectories show that the same polymer strand is capable of exhibiting a range of enhancement levels. The "off" periods on the Au substrate are exceptionally long and erratic. This behavior is attributed to sporadic electron transfer events between the strand and the metal. Bulk P3HT deposited on the same Au-nanowire array shows a dramatic reduction of the yield and lifetime of singlet excitons in comparison with the glass support, indicating that the proximity of the metal greatly accelerates both exciton dissociation and charge recombination. Interestingly, a large increase of the triplet exciton population is observed in the presence of the metal, indicating a much faster loss of the spin−spin correlation. The bulk P3HT results suggest that the large fluorescence enhancement observed in the single molecule experiments occurs only for a few emitters which have been fortuitously placed at the optimum distance and orientation with respect to the metal.

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Spectral tuning of the phosphorescence from metalloporphyrins attached to gold nanorods

Cited by 7 publications

References 48 publications

Surface morphology and optical properties of porphyrin/Au and Au/porphyrin/Au systems

Surface morphology and optical properties of porphyrin/Au and Au/porphyrin/Au systems

Extreme Enhancement of Single-Molecule Fluorescence from Porphyrins Induced by Gold Nanodimer Antennas

Excited State Behavior of Single Strand and Bulk P3HT in Contact with a Au-Nanowire Array

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