Improved power efficiency in deep blue phosphorescent organic light-emitting diodes using an acridine core based hole transport material

The NHC-Ir complexes f-IrSiPr, m-IrSiPr, and m-IrSMe, in which a dibenzothiophene (DBT) moiety is used to increase the emission efficiency for deep-blue phosphorescence, were synthesized and compared with the dibenzofuran...

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Solution-Processed Efficient Blue Phosphorescent Organic Light-Emitting Diodes (PHOLEDs) Enabled by Hole-Transport Material Incorporated Single Emission Layer

Materials ◽

10.3390/ma14030554 ◽

2021 ◽

Vol 14 (3) ◽

pp. 554

Author(s):

Taeshik Earmme

Keyword(s):

Light Emitting Diodes ◽

Blue Emission ◽

Hole Transport ◽

Organic Light Emitting Diodes ◽

Emission Layer ◽

Solution Processed ◽

Light Emitting ◽

Organic Light ◽

Single Emission ◽

Blue Phosphorescent

Solution-processed blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a single emission layer with small-molecule hole-transport materials (HTMs) are demonstrated. Various HTMs have been readily incorporated by solution-processing to enhance hole-transport properties of the polymer-based emission layer. Poly(N-vinylcarbazole) (PVK)-based blue emission layer with iridium(III) bis(4,6-(di-fluorophenyl)pyridinato-N,C2′)picolinate (FIrpic) triplet emitter blended with solution-processed 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) gave luminous efficiency of 21.1 cd/A at a brightness of 6220 cd/m2 with an external quantum efficiency (EQE) of 10.6%. Blue PHOLEDs with solution-incorporated HTMs turned out to be 50% more efficient compared to the reference device without HTMs. The high hole mobility, high triplet energy of HTM, and favorable energy transfer between HTM blended PVK host and FIrpic blue dopant were found to be important factors for achieving high device performance. The results are instructive to design and/or select proper hole-transport materials in solution-processed single emission layer.

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Dibenzothiophene derivatives as host materials for high efficiency in deep blue phosphorescent organic light emitting diodes

Journal of Materials Chemistry ◽

10.1039/c1jm12421h ◽

2011 ◽

Vol 21 (38) ◽

pp. 14604 ◽

Cited By ~ 76

Author(s):

Sook Hee Jeong ◽

Jun Yeob Lee

Keyword(s):

High Efficiency ◽

Light Emitting Diodes ◽

Organic Light Emitting Diodes ◽

Light Emitting ◽

Deep Blue ◽

Organic Light ◽

Host Materials ◽

Blue Phosphorescent

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Plastic Multilayered Molecular Organic Light Emitting Diodes

MRS Proceedings ◽

10.1557/proc-488-33 ◽

1997 ◽

Vol 488 ◽

Cited By ~ 2

Author(s):

George M. Daly ◽

Hideyuki Murata ◽

Charles D. Merritt ◽

Zakya H. Kafafi ◽

Hiroshi Inada ◽

...

Keyword(s):

Quantum Yield ◽

Power Efficiency ◽

Light Emitting Diodes ◽

Hole Transport ◽

Organic Light Emitting Diodes ◽

Electron Transport Layer ◽

Light Emitting ◽

Organic Light ◽

Device Structures ◽

External Quantum Yield

AbstractEnhanced performance has been observed for plastic molecular organic light emitting diodes (MOLEDs) consisting of two to four organic layers sequentially vacuum vapor deposited onto patterned indium-tin oxide (ITO) on polyester films. For all device structures studied, the performance of plastic diodes is comparable to or better than their analogs on glass substrates. At 100 A/m2, a luminous power efficiency of 4.4 lm/W and external quantum yield of 2.7% are measured for a device structure consisting of two hole transport layers, a doped emitting layer and an electron transport layer on a polyester substrate. The same device made on a silica substrate has a luminous power efficiency of 3.5 lm/W and external quantum yield of 2.3%. Electrical and optical performance for comparable device structures has been characterized by current-voltage-luminance measurements and electroluminescence spectra collected normal to the emitting surface. In addition, an integrating sphere was used to collect the total light emitted and to determine the optical output coupling on glass versus plastic substrates.

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