Fluorescence and Phosphorescence in Organic Materials

Köhler, Anna; Wilson, Joanne S.; Friend, Richard H.

doi:10.1002/1521-4095(20020517)14:10<701::aid-adma701>3.0.co;2-4

Cited by 386 publications

(215 citation statements)

References 31 publications

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“…It is well known that in strongly confined systems, such as organic crystals, excitation of nearby molecules can result in annihilation of excitons due to their strong interactions [50][51][52]. The exciton-exciton annihilation has also been observed in one-dimensional structures, such as semiconducting carbon nanotubes [53,54].…”

Section: Exciton-exciton Annihilationmentioning

confidence: 99%

Exciton-exciton annihilation in MoSe2monolayers

et al. 2014

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We investigate the excitonic dynamics in MoSe 2 monolayer and bulk samples by femtosecond transient absorption. Excitons are resonantly injected by a 750-nm and 100-fs laser pulse, and are detected by measuring a differential reflection of a probe pulse tuned in the range 790-820 nm. We observe a strong density-dependent initial decay of the exciton population in monolayers, which can be well described by the exciton-exciton annihilation. Such a feature is not observed in a bulk sample under comparable conditions. We also observe the saturated absorption induced by excitons in both monolayers and the bulk in the differential reflection measurements, which indicates their potential applications as saturable absorbers.

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Section: Exciton-exciton Annihilationmentioning

confidence: 99%

Exciton-exciton annihilation in MoSe2monolayers

et al. 2014

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“…[1][2][3] A considerable number of studies have been devoted to understanding the effect of electronic interactions between chains of conjugated polymer on the luminescence quantum yield of solid films of these polymers. 4 There seems to be consensus now that interchain interactions can lead to excitations that are delocalized over more than one polymer chain.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the vibronic fine structure in circularly polarized emission spectra from chiral molecular aggregates

Spano

Zhen

Meskers

2004

The Journal of Chemical Physics

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Using a Frenkel-exciton model, the degree of circular polarization of the luminescence (g lum ) from one-dimensional, helical aggregates of chromophoric molecules is investigated theoretically. The coupling between the electronic excitation and a local, intramolecular vibrational mode is taken into account. Analytical expressions for the fluorescence band shape and g lum are presented for the case of strong and weak electronic coupling between the chromophoric units. Results are compared to those from numerical calculations obtained using the three particle approximation. g lum for the 0-0 vibronic band is found to be independent of the relative strength of electronic coupling between chromophores and excitation-vibration coupling. It depends solely on the number of coherently coupled molecules. In contrast, for the higher vibronic transitions ͉g lum ͉ decreases with decreasing strength of the electronic coupling. In the limit of strong electronic coupling, ͉g lum ͉ is almost constant throughout the series of vibronic transitions but for weak coupling ͉g lum ͉ becomes vanishingly small for all vibronic transitions except for the 0-0 transition. The results are interpreted in terms of dynamic localization of the excitation during the zero point vibrational motion in the excited state of the aggregate. It is concluded that circular polarization measurements provide an independent way to determine the coherence size and bandwidth of the lowest exciton state for chiral aggregates.

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“…Fig. 2 shows the absorption and emission spectra of the Ir(III) complexes (1)(2)(3)(4), and their data is summarized in Table 1. The absorption spectra of Ir(III) complexes 1-4 below 360 nm were assigned to the spin-allowed 1 π-π * transition involving Bzppy (benzoylphenyl pyridine) ligands, and the band at approximately 400 nm to a spin-allowed metal charge transfer ( 1 MLCT) band.…”

Section: Resultsmentioning

confidence: 99%

“…[1][2][3] In addition, it is possible to increase their internal quantum efficiency to 100%, corresponding to an external quantum efficiency of > 20%. 4,5 These devices employ phosphorescent heavy metal complexes as the emitting materials that emit in the triplet metal-to-ligand charge transfer ( 3 MLCT) state.…”

Section: Introductionmentioning

confidence: 99%

“…4,5 These devices employ phosphorescent heavy metal complexes as the emitting materials that emit in the triplet metal-to-ligand charge transfer ( 3 MLCT) state. 6,7 Ir(III) complexes are the most popular electrophosphorescent emitting materials owing to their high efficiency and facile color tuning compared. [8][9][10] Recently, a variety of Ir(III) complexes have been developed as electrophosphorescent emitters.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Highly Efficient Red Phosphorescent OLEDs Based on Ir(III) Complexes with Fluorine-substituted Benzoylphenylpyridine Ligand

Kang¹,

Lee²,

Lee³

et al. 2010

Bulletin of the Korean Chemical Society

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Four orange-red phosphorescent Ir(III) complexes were designed and synthesized based on the benzoylphenylpyridine ligand with a fluorine substituent. Multilayered OLEDs with the device structure, ITO/2-TNATA/NPB/CBP : 8% Ir(III) complexes/BCP/Liq/Al, were fabricated using these complexes as dopant materials. All the devices exhibited orange-red electroluminescence and their electroluminescent properties were quite sensitive to the structural features of the dopants in the emitting layers. Among these, the maximum luminance (14700 cd/m 2 at 14.0 V) was observed in the device containing Ir(III) complex 1 as the dopant. In addition, its luminous, power and quantum efficiency were 11.7 cd/A, 3.88 lm/W and 9.58% at 20 mA/cm 2 , respectively. The peak wavelength of electroluminescence was 606 nm with CIE coordinates of (0.61, 0.38) at 12.0 V. The device also showed stable color chromaticity with various voltages.

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Fluorescence and Phosphorescence in Organic Materials

Cited by 386 publications

References 31 publications

Exciton-exciton annihilation in MoSe2monolayers

Exciton-exciton annihilation in MoSe2monolayers

Analysis of the vibronic fine structure in circularly polarized emission spectra from chiral molecular aggregates

Highly Efficient Red Phosphorescent OLEDs Based on Ir(III) Complexes with Fluorine-substituted Benzoylphenylpyridine Ligand

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