Origin of efficiency roll-off for FIrpic based blue organic light-emitting diodes and implications on phosphorescent molecule design

Jia Wang; Han Zhang; Wenyu Ji; Hanzhuang Zhang; Fu Rong ZHU

doi:10.7567/JJAP.54.101601

Origin of efficiency roll-off for FIrpic based blue organic light-emitting diodes and implications on phosphorescent molecule design

Jia Wang, Han Zhang, Wenyu Ji, Hanzhuang Zhang, Fu Rong ZHU

Research output: Contribution to journal › Journal article › peer-review

3 Citations (Scopus)

Abstract

This work reports our effort on understanding the efficiency roll-off in blue phosphorescent organic light-emitting diodes (OLEDs), based on bis[3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)]-iridium (FIrpic) doped in 4,4-N,N-dicarbazole-biphenyl (CBP) host. The performance of a set of blue phosphorescent OLEDs with different FIrpic dopant concentrations was analyzed. Unusually, the device having a 30-nm-thick pure FIrpic emissive layer with a high luminous efficiency of 7.76 cd/A at 100mA/cm2 was obtained. Theoretical calculation, based on the density functional theory, reveals that the exciton self-quenching process is suppressed due to the strong Coulomb repulsion between FIrpic molecules. It is found that the efficiency roll-off in FIrpic-based OLEDs is closely related to the exciton quenching induced by the CBP+ radical cations that are present in the CBP host.

Original language	English
Article number	101601
Journal	Japanese Journal of Applied Physics
Volume	54
Issue number	10
DOIs	https://doi.org/10.7567/JJAP.54.101601
Publication status	Published - 1 Oct 2015

Scopus Subject Areas

Engineering(all)
Physics and Astronomy(all)

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@article{2ec2ce08a09d40989913920d96b8ee43,

title = "Origin of efficiency roll-off for FIrpic based blue organic light-emitting diodes and implications on phosphorescent molecule design",

abstract = "This work reports our effort on understanding the efficiency roll-off in blue phosphorescent organic light-emitting diodes (OLEDs), based on bis[3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)]-iridium (FIrpic) doped in 4,4-N,N-dicarbazole-biphenyl (CBP) host. The performance of a set of blue phosphorescent OLEDs with different FIrpic dopant concentrations was analyzed. Unusually, the device having a 30-nm-thick pure FIrpic emissive layer with a high luminous efficiency of 7.76 cd/A at 100mA/cm2 was obtained. Theoretical calculation, based on the density functional theory, reveals that the exciton self-quenching process is suppressed due to the strong Coulomb repulsion between FIrpic molecules. It is found that the efficiency roll-off in FIrpic-based OLEDs is closely related to the exciton quenching induced by the CBP+ radical cations that are present in the CBP host.",

author = "Jia Wang and Han Zhang and Wenyu Ji and Hanzhuang Zhang and ZHU, {Fu Rong}",

note = "Publisher Copyright: {\textcopyright} 2015 The Japan Society of Applied Physics.",

year = "2015",

month = oct,

day = "1",

doi = "10.7567/JJAP.54.101601",

language = "English",

volume = "54",

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T1 - Origin of efficiency roll-off for FIrpic based blue organic light-emitting diodes and implications on phosphorescent molecule design

AU - Wang, Jia

AU - Zhang, Han

AU - Ji, Wenyu

AU - Zhang, Hanzhuang

AU - ZHU, Fu Rong

PY - 2015/10/1

Y1 - 2015/10/1

N2 - This work reports our effort on understanding the efficiency roll-off in blue phosphorescent organic light-emitting diodes (OLEDs), based on bis[3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)]-iridium (FIrpic) doped in 4,4-N,N-dicarbazole-biphenyl (CBP) host. The performance of a set of blue phosphorescent OLEDs with different FIrpic dopant concentrations was analyzed. Unusually, the device having a 30-nm-thick pure FIrpic emissive layer with a high luminous efficiency of 7.76 cd/A at 100mA/cm2 was obtained. Theoretical calculation, based on the density functional theory, reveals that the exciton self-quenching process is suppressed due to the strong Coulomb repulsion between FIrpic molecules. It is found that the efficiency roll-off in FIrpic-based OLEDs is closely related to the exciton quenching induced by the CBP+ radical cations that are present in the CBP host.

AB - This work reports our effort on understanding the efficiency roll-off in blue phosphorescent organic light-emitting diodes (OLEDs), based on bis[3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)]-iridium (FIrpic) doped in 4,4-N,N-dicarbazole-biphenyl (CBP) host. The performance of a set of blue phosphorescent OLEDs with different FIrpic dopant concentrations was analyzed. Unusually, the device having a 30-nm-thick pure FIrpic emissive layer with a high luminous efficiency of 7.76 cd/A at 100mA/cm2 was obtained. Theoretical calculation, based on the density functional theory, reveals that the exciton self-quenching process is suppressed due to the strong Coulomb repulsion between FIrpic molecules. It is found that the efficiency roll-off in FIrpic-based OLEDs is closely related to the exciton quenching induced by the CBP+ radical cations that are present in the CBP host.

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DO - 10.7567/JJAP.54.101601

M3 - Journal article

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SN - 0021-4922

VL - 54

JO - Japanese Journal of Applied Physics

JF - Japanese Journal of Applied Physics

IS - 10

M1 - 101601

ER -

Origin of efficiency roll-off for FIrpic based blue organic light-emitting diodes and implications on phosphorescent molecule design

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