Field-Induced Photoluminescence Modulation of MEH−PPV under Near-Field Optical Excitation

McNeill, Jason; O'Connor, Donald; Adams, and David M.; Barbara, Paul F.; Kämmer, Stefan

doi:10.1021/jp002591l

Cited by 48 publications

(62 citation statements)

References 41 publications

(68 reference statements)

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“…Other studies by the Vardeny and Barbara groups have identified efficient luminescent quenching by polarons in PPV derivatives like DOO-PPV, 30 aggregates of a porphyrin derivative 31 and MEH-PPV. 32,33 In the latter case, 32 a Stern-Volmer quenching constant of 7ϫ10 Ϫ19 cm 3 was obtained, which implied that a single charge could quench over a thousand surrounding chromophores. Our quenching constant ␥ d is related to the Stern-Volmer constant K via…”

Section: Discussionmentioning

confidence: 92%

The role of long-lived dark states in the photoluminescence dynamics of poly(phenylene vinylene) conjugated polymers. II. Excited-state quenching versus ground-state depletion

Lim

Bjorklund

Bardeen

2003

The Journal of Chemical Physics

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The two pulse fluorescence bleaching experiments reported in an earlier paper ͓J. Chem. Phys. 117, 454 ͑2002͔͒ are reanalyzed in the context of additional experiments. The fluorescence bleaching observed in that paper was originally ascribed to ground-state depletion. By analyzing the absorption saturation behavior and the magnitude of the pump-probe signal, we find that the absorption cross section of poly͑phenylene vinylene͒ at 400 nm is two orders of magnitude too small to significantly deplete the ground state given the pump fluences used in that experiment. Instead, the observed depletion is due to a combination of exciton-exciton annihilation at early times and dark state luminescence quenching at later times. Different experiments have different sensitivities to the fluence-dependent quenching, with time-resolved experiments like transient emission and fluorescence decay time consistently underestimating the exciton-exciton annihilation rate. Experiments that measure the integrated fluorescence, such as fluorescence saturation and bleaching, result in a consistent value for the exciton-exciton annihilation constant of 6 ϫ10 Ϫ9 cm 3 /s, while the dark state quenching constant is estimated to be at least 1.2 ϫ10 Ϫ8 cm 3 /s. Indirect evidence based on the wavelength and sample dependence of the dark state formation suggest that the dark states are charge-separated polarons. The relatively large quenching constants are consistent with what has been observed in other conjugated polymers and suggest that the long-lived dark states in particular are effective quenchers, capable of quenching thousands of surrounding chromophores.

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Section: Discussionmentioning

confidence: 92%

The role of long-lived dark states in the photoluminescence dynamics of poly(phenylene vinylene) conjugated polymers. II. Excited-state quenching versus ground-state depletion

Lim

Bjorklund

Bardeen

2003

The Journal of Chemical Physics

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“…Detailed studies of the time dynamics of ensemble fluorescence quenching,218 the concentration dependence in blends,219 and the morphology correlation using nearfield scanning optical‐probe techniques220 revealed that, under certain circumstances, electric fields can also amplify the fluorescence. This effect can result from field‐induced recombination from charge‐separated states.…”

Section: Single Polymer Chains In Devicesmentioning

confidence: 99%

Single‐Molecule Spectroscopy for Plastic Electronics: Materials Analysis from the Bottom‐Up

2010

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pi-conjugated polymers find a range of applications in electronic devices. These materials are generally highly disordered in terms of chain length and chain conformation, besides being influenced by a variety of chemical and physical defects. Although this characteristic can be of benefit in certain device applications, disorder severely complicates materials analysis. Accurate analytical techniques are, however, crucial to optimising synthetic procedures and assessing overall material purity. Fortunately, single-molecule spectroscopic techniques have emerged as an unlikely but uniquely powerful approach to unraveling intrinsic material properties from the bottom up. Building on the success of such techniques in the life sciences, single-molecule spectroscopy is finding increasing applicability in materials science, effectively enabling the dissection of the bulk down to the level of the individual molecular constituent. This article reviews recent progress in single molecule spectroscopy of conjugated polymers as used in organic electronics.

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“…McNeill et al [113,114] studied the near-field photoluminescence of thin-film MEH-PPV induced by a voltage bias applied between the near-field probe and the substrate. The goal was to investigate the field-induced modulation of the local carrier density.…”

Section: Near-field Scanning Optical Microscopy (Nsom)mentioning

confidence: 99%

Nanoscale Inhomogeneity of Conducting‐Polymer‐Based Materials

Pailleret

Semenikhin

2010

Nanostructured Conductive Polymers

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Field-Induced Photoluminescence Modulation of MEH−PPV under Near-Field Optical Excitation

Cited by 48 publications

References 41 publications

The role of long-lived dark states in the photoluminescence dynamics of poly(phenylene vinylene) conjugated polymers. II. Excited-state quenching versus ground-state depletion

The role of long-lived dark states in the photoluminescence dynamics of poly(phenylene vinylene) conjugated polymers. II. Excited-state quenching versus ground-state depletion

Single‐Molecule Spectroscopy for Plastic Electronics: Materials Analysis from the Bottom‐Up

Nanoscale Inhomogeneity of Conducting‐Polymer‐Based Materials

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