Harvesting Singlet and Triplet Energy in Polymer LEDs

Cleave, Vicki; Yahioglu, Gökhan; Barny, P. Le; Friend, Richard H.; Tessler, Nir

doi:10.1002/(sici)1521-4095(199903)11:4<285::aid-adma285>3.3.co;2-e

Cited by 118 publications

(190 citation statements)

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“…7 F 2 transition of Eu 3 which has a radiative lifetime < 100 ms. In OLEDs, Eu(DBM) 3 (Phen) is preferably codeposited with a charge transport material such as [17] biphenyl-p-(tbutyl)phenyl-1,3,4-oxadiazole (PBD), thereby reducing self-quenching and improving charge carrier mobilities.…”

Section: Lanthanide Complexesmentioning

confidence: 99%

“…However, since the relevant triplet energy levels in the host and the guest triplet state are frequently unknown and, moreover, are dif®cult to quantify due to their small oscillator strengths, optimizing guest-host systems for resonant triplet transfer is problematic. In the case of Eu(DBM) 3 (Phen), the energy of ligand phosphorescence [18] is large (< 2.6 eV) and the triplet absorption energy is expected to be even higher. Hence triplet transfer from the host to the ligand requires a host triplet of suf®ciently high energy to be in resonance with the guest, and a device structure that minimizes nonradiative losses of host triplets.…”

Section: Lanthanide Complexesmentioning

confidence: 99%

“…Hence, PtOEP cannot be an ef®cient electron trap, since carriers removed by PtOEP in device 2 would result in a decrease in the DCM2 and Alq 3 emission: an effect clearly not observed. Since the DCM2 acts as a`®lter' that removes singlet Alq 3 excitons, the only possible origin of the PtOEP luminescence is Alq 3 triplet states that have diffused through the DCM2 and intervening Alq 3 layers.…”

Section: Organometallic Phosphorsmentioning

confidence: 99%

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Phosphorescent materials for application to organic light emitting devices

Baldo¹,

Thompson²,

Forrest³

1999

Pure and Applied Chemistry

385

207

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Organic phosphors have demanded the attention of the organic electroluminescence community because they enable ef®ciencies quadruple that of¯uorescent materials. In this work, we review the categories of organic phosphors: lanthanide complexes, organic phosphors and metal-organic complexes. The characteristics necessary for ef®cient phosphorescence are considered and conclusions are drawn as to the most promising materials.

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Section: Lanthanide Complexesmentioning

confidence: 99%

Section: Lanthanide Complexesmentioning

confidence: 99%

Section: Organometallic Phosphorsmentioning

confidence: 99%

See 1 more Smart Citation

Phosphorescent materials for application to organic light emitting devices

Baldo¹,

Thompson²,

Forrest³

1999

Pure and Applied Chemistry

385

207

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“…OLEDs are heterojunction devices in which layers of organic transport materials are usually incorporated into devices as amorphous thin solid films [8]. Organometallic complexes are suitable candidates for OLEDs [9][10][11][12][13][14][15][16][17][18] due to their stability, emission-color purity, and availability both as singlet [19] and triple emitters [20] and their ease of deposition by means of thermal vacuum evaporation. Following the initial report of utilization of mer-Alq3 as electron transport material and emitting layer in OLED [21,22], the derivatives of metal quinolates has become the focus of new electroluminescent materials research with mer-Alq3 being the most often used [8,23,24].…”

Section: Introductionmentioning

confidence: 99%

Push-pull effect on the geometrical, optical and charge transfer properties of disubstituted derivatives of mer-tris(4-hydroxy-1,5-naphthyridinato) aluminum (mer-AlND3)

Rao

Bhanuprakash

2016

Open Chemistry

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Push-pull effect on the geometrical, optical and charge transfer properties of disubstituted derivatives of mer-tris(4-hydroxy-1,5-naphthyridinato) aluminum (mer-AlND3) DOI: 10.1515/chem-2016-0001 received April 23, 2015 accepted November 14, 2015. Abstract: To design innovative and novel optical materials with high mobility, two kinds of disubstituted derivatives for mer-tris(4-hydroxy-1,5-naphthyridinato) aluminum (mer-AlND3) with push (EDG)-pull (EWG) substituents have been designed. The structures of mer-tris(8-EDG-2-EWG-4-hydroxy-1,5-naphthyridinato) aluminum (type I) and mer-tris(8-EWG-2-EDG-4-hydroxy-1,5-naphthyridinato) aluminum (type II) in the ground and first excited states have been optimized at the B3LYP/6-31G(D) and CIS/6-31G(D) level of theory, respectively. It can be seen from frontier molecular orbitals analysis, in all these complexes, the highest occupied molecular orbital (HOMO) is localized on the pyridine-4-ol ring of A-ligand while lowest unoccupied molecular orbital (LUMO) is on the pyridyl ring of B-ligand in ground state irrespective of electron donor/acceptor substitution present on the ligands similar to that of mer-tris(8-hydroxyquinoline) aluminum (mer-Alq3) and parent mer-AlND3.The absorption and emission wavelengths have been evaluated at the TD-PBE0/6-31G(D) level and it can be see that all the type I derivatives show blue shift while most of the type II derivatives show red shift compared to mer-AlND3. All the disubstituted complexes have showed hypsochromic shifts in both the absorption and emission spectra when compared with the calculated absorption and emission spectra respectively of mer-Alq3. It can be seen that the reorganization energies of some of the disubstituted derivatives are comparable with merAlq3 and these derivatives might be good candidates for emitting materials in OLED.

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“…In particular, electroluminescent devices based on phosphorescent organic molecules have received considerable attention due to their ability of generating light from both singlet and triplet excitons which can lead to remarkably high efficiencies. [1][2][3][4] Maximum internal quantum efficiencies approaching 100% have been demonstrated in OLEDs using phosphorescent organometallic complexes based on iridium͑III͒. 5,6 An external electroluminescence quantum efficiency ͑EQE͒ of 19% has already been reported in devices using a green emitting cyclometalated iridium͑III͒ complex.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2008

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We study photoluminescence and triplet-triplet exciton annihilation in a neat film of a fac-tris͑2-phenylpyridyl͒iridium͑III͒ ͓Ir͑ppy͒ 3 ͔-cored dendrimer and in its blend with a 4 , 4Ј-bis͑N-carbazolyl͒biphenyl host for the temperature range of 77-300 K. The nearest neighbor hopping rate of triplet excitons is found to increase by a factor of 2 with temperature between 150 and 300 K and is temperature independent at lower temperature. The intermolecular quenching rate follows the Arrhenius law with an activation energy of 7 meV, which can be explained by stronger dipole-dipole interactions with the donor molecule in the higher triplet substate. The results indicate that energy disorder has no significant effect on triplet transport and quenching in these materials.

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Harvesting Singlet and Triplet Energy in Polymer LEDs

Cited by 118 publications

References 0 publications

Phosphorescent materials for application to organic light emitting devices

Phosphorescent materials for application to organic light emitting devices

Push-pull effect on the geometrical, optical and charge transfer properties of disubstituted derivatives of mer-tris(4-hydroxy-1,5-naphthyridinato) aluminum (mer-AlND3)

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

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