Triplet exciton transfer mechanism between phosphorescent organic dye molecules

Steinbacher, Frank; Krause, Ralf; Hunze, Arvid; Winnacker, A.

doi:10.1002/pssa.201127451

Cited by 24 publications

(19 citation statements)

References 25 publications

(30 reference statements)

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“…Since almost all modern OLEDs rely on phosphors to achieve high efficiency, long range energy transfer is crucial for many OLED processes. For example, triplettriplet annihilation and triplet-triplet phosphor energy transfer have both been shown to follow the distance dependences predicted by Förster's theory [11]- [13] . It was also pointed out by Förster himself, in his initial formulation that his mechanism would be applicable to triplets if the radiative triplet to ground state transition could compete with the nonradiative transition [14] and was first verified not long afterwards experimentally [15] .…”

Section: Elimination Of Exciton Quenchingmentioning

confidence: 91%

Device design for optimal exciton harvesting

Ingram¹,

Lu²

2014

SPIE Proceedings

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Organic light emitting diodes (OLEDs) show potential as the next generation solid state lighting technology. A major barrier to widespread adoption at this point is the efficiency droop that occurs for OLEDs at practical brightness (~ 5000 cd/m 2 ) levels necessary for general lighting. We highlight recent progress in highly efficient OLEDs at high brightness, where improvements are made by managing excitons in these devices through rational device design. General design principles for monochrome OLEDs are discussed based on recent device architectures that have been successfully implemented. We expect that an improved understanding of exciton dynamics in OLEDs in combination with innovative device design will drive future development.

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Section: Elimination Of Exciton Quenchingmentioning

confidence: 91%

Device design for optimal exciton harvesting

Ingram¹,

Lu²

2014

SPIE Proceedings

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“…In certain situations triplet excitons may act as donors in Förster-type energy transfer when the radiative transition from triplet to ground state is competitive with other transitions [15,16]. One situation meeting this criteria is Ir-based emitters that have a high rate of radiative triplet to ground state transitions because of enhanced spin orbit coupling caused by the heavy metal atom [17][18][19][20].…”

Section: Theorymentioning

confidence: 96%

Probing the exciton distribution in organic light-emitting diodes using long-range energy transfer

Ingram

Chang

2014

Can. J. Phys.

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We present a technique to probe the exciton distribution in organic light-emitting diodes. Our method involves strategically inserting sensing layers at different locations in proximity to the emissive zone. In contrast to typical sensing layers that act as a probe of the local exciton density, the sensing layers reported here use long-range energy transfer to probe a large area around the sensing layer. We highlight the importance of material selection, such that exciton distribution could be probed without influencing the electrical and optical properties of the organic light-emitting diodes. We expect that this work will provide an invaluable tool for studying excitons in organic light-emitting diodes. PACS Nos.: 78.60.Fi, 71.35.Aa, 42.70.Jk.Résumé : Nous présentons une technique pour sonder le nombre d'excitons dans des diodes électroluminescentes organiques. Notre méthode demande d'introduire stratégiquement des couches senseurs à différentes localisations près de la zone d'émission. Contrairement aux couches senseurs typiques qui jouent le rôle de sonde de la densité locale d'excitons, les couches senseurs dont il est question ici utilisent un transfert d'énergie à longue portée pour sonder une grande surface autour de la couche senseur. Nous soulignons l'importance de la sélection du matériau, afin que la distribution d'excitons puisse être sondée sans influencer les propriétés électriques et optiques des diodes électroluminescentes organiques. Nous sommes confiants que notre travail fournira un outil très utile pour l'étude des excitons dans les diodes électroluminescences organiques. [Traduit par la Rédaction]

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“…where t S is the lifetime of singlet excitons, t T is the lifetime of triplet excitons, R da is the D-A distance of separation, R f (R d ) is the Fçrster (Dexter) radius, and L is the average length of a molecular orbital, which is found to be 0.11 nm [16] in Ir(ppy) 3 . We have assumed the same value here for all triplet exciton calculations.…”

Section: Exciton Diffusionmentioning

confidence: 99%

Diffusion Length and Langevin Recombination of Singlet and Triplet Excitons in Organic Heterojunction Solar Cells

Ompong

Singh

2015

ChemPhysChem

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We derived new expressions for the diffusion length of singlet and triplet excitons by using the Föster and Dexter transfer mechanisms, respectively, and have found that the diffusion lengths of singlet and triplet excitons are comparable. By using the Langevin recombination theory, we derived the rate of recombination of dissociated free charges into their excitonic states. We found that in some organic polymers the probabilities of recombination of free charge carriers back into the singlet and triplet states are approximately 65.6 and 34.4 %, respectively, indicating that Langevin-type recombination into triplet excitons in organic semiconductors is less likely. This implies that the creation of triplet excitons may be advantageous in organic solar cells, because this may lead to dissociated free charge carriers that can be collected at their respective electrodes, which should result in better conversion efficiency.

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Triplet exciton transfer mechanism between phosphorescent organic dye molecules

Cited by 24 publications

References 25 publications

Device design for optimal exciton harvesting

Device design for optimal exciton harvesting

Probing the exciton distribution in organic light-emitting diodes using long-range energy transfer

Diffusion Length and Langevin Recombination of Singlet and Triplet Excitons in Organic Heterojunction Solar Cells

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