Temperature dependence of the triplet diffusion and quenching rates in films of an<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Ir</mml:mi><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>ppy</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>-cored dendrimer

Ribierre, Jean Charles; Ruseckas, Arvydas; Samuel, Ifor D. W.; Staton, S.V.; Burn, Paul L.

doi:10.1103/physrevb.77.085211

Cited by 25 publications

(10 citation statements)

References 35 publications

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“…Ribierre et al observed a similar temperature dependence of the time-averaged hopping rate of triplet excitons in phosphorescent iridium-cored metal–ligand charge transfer complexes using triplet–triplet annihilation. 122 …”

Section: Excitation Energy Transfer To Heterojunctionmentioning

confidence: 99%

Light Harvesting for Organic Photovoltaics

2016

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The field of organic photovoltaics has developed rapidly over the last 2 decades, and small solar cells with power conversion efficiencies of 13% have been demonstrated. Light absorbed in the organic layers forms tightly bound excitons that are split into free electrons and holes using heterojunctions of electron donor and acceptor materials, which are then extracted at electrodes to give useful electrical power. This review gives a concise description of the fundamental processes in photovoltaic devices, with the main emphasis on the characterization of energy transfer and its role in dictating device architecture, including multilayer planar heterojunctions, and on the factors that impact free carrier generation from dissociated excitons. We briefly discuss harvesting of triplet excitons, which now attracts substantial interest when used in conjunction with singlet fission. Finally, we introduce the techniques used by researchers for characterization and engineering of bulk heterojunctions to realize large photocurrents, and examine the formed morphology in three prototypical blends.

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Section: Excitation Energy Transfer To Heterojunctionmentioning

confidence: 99%

Light Harvesting for Organic Photovoltaics

2016

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“…4,4-Bis(carbazol-9-yl)-2,2-biphenyl (CBP, Scheme 1) is a typical host molecule of the luminescent layer. While there have been many experimental studies on the photo-luminescent properties of Ir(ppy) 3 in a CBP layer [17][18][19][20], no geometrical structure has been reported for the mixture of Ir(ppy) 3 and CBP. Thus it is necessary to assume some reasonable orientation in the amorphous layer.…”

Section: Introductionmentioning

confidence: 97%

Theoretical study on the absorption spectra of fac-Ir(ppy)3 in the amorphous phase of organic electro-luminescent devices

et al. 2009

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Absorption spectra in the amorphous phase consisting of Ir(ppy) 3 and 4,4-bis(carbazol-9-yl)-2,2-biphenyl (CBP) molecules were theoretically investigated. The equilibrium structures in amorphous phase were simulated by QM/MM MD calculations. The results of calculation suggest that eleven CBP molecules exist as the closest neighbors of Ir(ppy) 3 . Time-dependent density functional theory (TD-DFT) calculations successfully reproduced the experimental absorption spectra. For Ir(ppy) 3 in the gas phase, the most important spectral peak at the wavelength of 400 nm can be assigned principally to the one-electron excitation from HOMO-1 to LUMO?2, where the main component of HOMO-1 is the d orbital of the Ir atom and that of LUMO?2 is the p* orbital of the ligands. When Ir(ppy) 3 strongly interacts with a CBP molecule, the p* orbital of the ligand is delocalized into the CBP molecule. This is the reason why the spectral peak at the wavelength of 400 nm almost disappears in the amorphous phase.

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“…This dendrimer was chosen for these measurements because its basic photophysical properties have been intensively studied in the past and are well documented. 12,14,15,19 An excitation wavelength of 325 nm was used in this case to get sufficient absorbance. The PLQY of the 180 nm thick film was found to be 68 AE 7%, dropping to 54 AE 5% and 29 AE 3% for film thicknesses of 140 and 60 nm respectively.…”

Section: Thickness Dependence Of the Phosphorescencementioning

confidence: 99%

“…In this paper, we explore surface quenching of phosphorescence in films of several fac-tris(2-phenylpyridyl)iridium(III) [Ir(ppy) 3 ]-cored dendrimers with different spacing between them, with the spacing controlled by the structure of the dendrimer as well as by blending with a large optical gap host. [14][15][16][17][18][19] The molecular structures of the first generation [Ir(ppy) 3 ]-cored dendrimers used in this work are shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Phosphorescence quenching of fac-tris(2-phenylpyridyl)iridium(iii) complexes in thin films on dielectric surfaces

Ribierre

Ruseckas

Staton

et al. 2016

Phys. Chem. Chem. Phys.

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We study the influence of the film thickness on the time-resolved phosphorescence and the luminescence quantum yield of fac-tris(2-phenylpyridyl)iridium(iii) [Ir(ppy)3]-cored dendrimers deposited on dielectric substrates. A correlation is observed between the surface quenching velocity and the quenching rate by intermolecular interactions in the bulk film, which suggests that both processes are controlled by dipole-dipole interactions between Ir(ppy)3 complexes at the core of the dendrimers. It is also found that the surface quenching velocity decreases as the refractive index of the substrate is increased. This can be explained by partial screening of dipole-dipole interactions by the dielectric environment.

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Temperature dependence of the triplet diffusion and quenching rates in films of anIr(ppy)3-cored dendrimer

Cited by 25 publications

References 35 publications

Light Harvesting for Organic Photovoltaics

Light Harvesting for Organic Photovoltaics

Theoretical study on the absorption spectra of fac-Ir(ppy)3 in the amorphous phase of organic electro-luminescent devices

Phosphorescence quenching of fac-tris(2-phenylpyridyl)iridium(iii) complexes in thin films on dielectric surfaces

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