Fluorescence blinking in MEH-PPV single molecules at low temperature

Mirzov, Oleg; Cichos, Frank; Borczyskowski, C. von; Scheblykin, Ivan G.

doi:10.1016/j.jlumin.2004.09.110

Cited by 16 publications

(29 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Fluorescence Of Thin Films and Blendsmentioning

confidence: 99%

“…triplet state) from which the system is not able to immediately fluoresce. 16 In polymers such as MEH-PPV, this phenomenon is expected to occur, since it presents several emitting moieties over which the exciton is delocalized 17 to achieve local excitation energy minima.53 MEH-PPV samples in this work contain several emitting moieties that present their own absorption and fluorescence spectra. There, blue-region fluorescent collapsed H-aggregates are excited by higher energy wavelengths and are believed to have a small contribution to the overall fluorescence of MEH-PPV usual systems.…”

mentioning

confidence: 90%

“…[15][16][17][18][19][20][21] Fluorescence lifetime measurements are useful, among other applications, to identify a single or multiple emitting species in a solid sample or in liquid solution. Bi-exponential decay curves usually indicate the occurrence of faster decays along with slower ones, which suggest the contribution of some non-radiative deactivation processes.…”

Section: Introductionmentioning

confidence: 99%

“…From fluorescence spectra in Figure 3, the observed intensity fluctuation of the fluorescence at 520-550 nm in films in comparison to solutions, is associated to a reversible and efficient energy migration, referred to as the blinking effect. 16 It is expected that an exciton lies in a temporary long-lived ''dark'' state (e.g. triplet state) from which the system is not able to immediately fluoresce.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Photoluminescence of Solvent-Selected Fluorescent Moieties in MEH-PPV Solutions and Films

Ribeiro¹,

Camargo²,

Pereira³

et al. 2017

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

In this work, we examined how photoluminescence in poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) is affected by morphology, dictated by the mode of preparation. For that, MEH-PPV dilute solutions in good and non-solvents, thick cast films with poly[methylmethacrylate] (PMMA) as inert matrix and spin-coated thin films were prepared. These systems were studied by steady-state and time-dependent fluorescence spectroscopy and electronic microscopy. Unexpected photoluminescent behavior was detected in solutions and films and it was related to different excitons modulated by MEH-PPV conformation. By semi empirical calculations we obtained the singlet and triplet state energies of an MEH-PPV model system and, from time-resolved fluorescence spectroscopy, the existence of short-lived excited states was revealed, enabling us to infer on possible singlet fission in MEH-PPV-based systems.Keywords: photoluminescence, morphology, thin films, time-resolved fluorescence, computational calculations IntroductionSince poly(phenylene-vinylene) (PPV) derivatives were found to be electroluminescent, 1 the search for a systematic method to determine their applications has been of great interest. Their mechanical, morphological and optical properties have been widely discussed and findings related these properties to preparation methods. Although there are many aspects regarding the effects of preparation methods on optical response, authors seem to agree that preparation method influences molecular conformation, enabling or inhibiting aggregation and, consequently, affecting inter and intrachain interactions. Processing parameters are believed to modify the conformation and assembling mechanisms of polymeric materials, resulting in a memory effect of the structural information that is replicated from solutions to solid films. Therefore, to understand the role of chain conformation in solution is of major importance for applications such as device fabrication, since properties can be tuned, enhancing the desired characteristics and suppressing the undesired ones. 2,3 For instance, it is well known that photoluminescence of PPV derivatives show prominent red-shift due to the enhancement of energy transfer as the π-electron delocalization increases. 4 As pointed out in an earlier work, 5 this red-shift indicates aggregation driven by π-π interactions as the conjugation length increases.In polymeric systems, several occurrences are responsible for chain torsions that impose limits to the length of conjugated segments, affecting the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps. They are interpreted as stabilization and/or destabilization of HOMO and LUMO levels. 6 These occurrences may be related to the presence of impurities, molecules of solvent that strongly interact with the polymer chains and a distribution of torsion angles promoted by molecular interactions of any nature. 6 In this situation, the densities of excited states (DOS) available for electronic chan...

show abstract

Section: Fluorescence Of Thin Films and Blendsmentioning

confidence: 99%

mentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Photoluminescence of Solvent-Selected Fluorescent Moieties in MEH-PPV Solutions and Films

Ribeiro¹,

Camargo²,

Pereira³

et al. 2017

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…Approximately 11 % of single molecules at 100 K and 48 % of single molecules at 293 K demonstrated clear fluorescence blinking behaviour-abrupt step-like fluctuation of intensity. [39,40] The blinking effect is usually explained as quenching of a part of the polymer chain by a photogenerated quencher (hole polaron). [12,[41][42][43] Weak temperature dependence was observed for < M > .…”

Section: Origin Of Correlation Values For Meh-ppvmentioning

confidence: 99%

Correlation Analysis of Fluorescence Intensity and Fluorescence Anisotropy Fluctuations in Single‐Molecule Spectroscopy of Conjugated Polymers

2010

View full text Add to dashboard Cite

Single-molecule spectroscopy techniques are used to investigate time fluctuations of the fluorescence properties of two different types of conjugated polymer, a polythiophene derivative (PDOPT) and a phenylene vinylene derivative (MEH-PPV), at 100 and 293 K. Linear correlation coefficients between fluorescence intensity and polarization are used to characterize fluctuations. We are able to distinguish between different blinking and bleaching effects on the polarization. Furthermore, the polarization data reveal clear differences in the topology of these two polymers, which is related to the ordered conformation of the MEH-PPV. Plots of correlation coefficients appear to be very different for the two polymers and are also very sensitive to temperature. These observations prove that correlation analysis is a useful tool to understand fluorescence fluctuations in multi-chromophoric systems.

show abstract

Polydispersity of the photoluminescence quantum yield in single conjugated polymer chains

Mirzov

Scheblykin

2005

Chemical Physics

View full text Add to dashboard Cite

Fluorescence blinking in MEH-PPV single molecules at low temperature

Cited by 16 publications

References 15 publications

Photoluminescence of Solvent-Selected Fluorescent Moieties in MEH-PPV Solutions and Films

Photoluminescence of Solvent-Selected Fluorescent Moieties in MEH-PPV Solutions and Films

Correlation Analysis of Fluorescence Intensity and Fluorescence Anisotropy Fluctuations in Single‐Molecule Spectroscopy of Conjugated Polymers

Polydispersity of the photoluminescence quantum yield in single conjugated polymer chains

Contact Info

Product

Resources

About