NOVEL BLUE ORGANIC LIGHT-EMITTING MATERIAL

2004 ◽  
Vol 13 (03n04) ◽  
pp. 649-653 ◽  
Author(s):  
YUN-HI KIM ◽  
HYUNG-SUN KIM ◽  
JUN-HWAN AHN ◽  
SUNG-HAN KIM ◽  
SOON-KI KWON
Keyword(s):  
Emission Band ◽  
Blue Emission ◽  
Luminous Efficiency ◽  
Full Width ◽  
Half Maximum ◽  
Device Structure ◽  
Light Emitting ◽  
Organic Light ◽  
Chromaticity Coordinates ◽  
Narrow Emission

The blue light-emitting material was synthesized. With the non-doped, blue-emitting material in the multilayer device structure, it was possible to achieve the luminous efficiency of 3.38 cd/A at 110 mA/cm2. The EL spectrum of the ITO / CuPc / NPB / BDPSP / Alq 3/ Mg : Ag device showed a narrow emission band with full width at half maximum (FWHM) 70 nm and λ max =448.25 nm . The emitting color of the device showed the highly pure blue emission (x,y)=(0.158, 0.10) for ITO / CuPc / NPB / BDPSP / Alq 3/ Mg : Ag in CIE (Commission Internationale de l'Eclairage) chromaticity coordinates.

Efficient organic light-emitting diodes with narrow emission bandwidths based on iridium(III) complexes with pyrido[3',2':4,5]pyrrolo[3,2,1-jk]carbazole unit

2021 ◽  
Author(s):  
Xiang-Ji Liao ◽  
Jin-Jun Zhu ◽  
Li Yuan ◽  
Zhi-Ping Yan ◽  
Zhen-Long Tu ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Luminous Efficiency ◽  
Organic Light Emitting Diodes ◽  
Color Purity ◽  
Full Width ◽  
Light Emitting ◽  
Organic Light ◽  
Narrow Emission

In order to realize efficient organic light-emitting diodes (OLEDs) with good color-purity, the iridium(III) (Ir(III)) emitters with high luminous efficiency and narrow full width at half maxima (FWHM) are required....

Theoretical and Experimental Studies on Microcavity Organic Light-Emitting Diodes with Different Emitters

2015 ◽  
Vol 645-646 ◽  
pp. 1087-1092 ◽  
Author(s):  
Cui Yun Peng ◽  
Meng Jie Wei ◽  
Rong Juan Huang ◽  
Kun Ping Guo ◽  
Yue Lin Jing ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Light Emitting Diodes ◽  
Experimental Studies ◽  
Experimental Results ◽  
Organic Light Emitting Diodes ◽  
Full Width ◽  
Half Maximum ◽  
Light Emitting ◽  
Organic Light ◽  
Electroluminescence Intensity

We have theoretically and experimentally investigated the microcavity organic light-emitting diodes (MOLEDs) that enhanced the emission intensity and narrowed the spectra simultaneously. In this work, MOLEDs with the reflectivities of 70% and 90% have been successfully fabricated. Comparing to non-cavity OLEDs, the maximum forward electroluminescence intensity and the peak luminescence can be improved by 6.8 times and 2.2 times, respectively. The full width at half maximum could be sharply narrowed to 10 nm. The different configurations of MOLEDs with varied emitting layers have also been evaluated which fitted well with the experimental results.

A green emitting iridium(III) complex with narrow emission band and its application to phosphorescence organic light-emitting diodes (OLEDs)

2009 ◽  
Vol 10 (6) ◽  
pp. 1066-1073 ◽  
Author(s):  
Sung Ouk Jung ◽  
Qinghua Zhao ◽  
Jong-Won Park ◽  
Seul Ong Kim ◽  
Yun-Hi Kim ◽  
...  
Keyword(s):  
Emission Band ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
Narrow Emission

High-Efficiency White Organic Light-Emitting Diodes Using Blue and Red Phosphorescent Materials with Exciton Blocking Layer

2008 ◽  
Vol 8 (9) ◽  
pp. 4607-4610
Author(s):  
Jung Hyun Park ◽  
Ji Hoon Seo ◽  
Ji Hyun Seo ◽  
Seok Jae Lee ◽  
Ja Ryong Koo ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Blue Emission ◽  
Luminous Efficiency ◽  
Organic Light Emitting Diodes ◽  
Blocking Layer ◽  
Maximum Luminance ◽  
Red Emission ◽  
Light Emitting ◽  
Organic Light

High-efficiency white organic light-emitting diodes (WOLEDs) were fabricated with two emissive layers and an exciton blocking layer (EBL) was sandwiched between two phosphorescent dyes, bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) as the blue emission and iridium(III) bis(5-acetyl-2-phenylpyridinato-N,C2′) acetylacetonate ((acppy)2Ir(acac)) as the red emission. This EBL effectively prevented a triple–triple energy transfer between the two phosphorescent emissive layers with blue and red emission. The white device showed Commission Internationale De L'Eclairage (CIEx,y) coordinates of (0.33, 0.42) at 22400 cd/m2, a maximum luminance of 27300 cd/m2 at 13.2 V, and a maximum luminous efficiency of 26.9 cd/A.

Deep Blue Organic Light-Emitting Diodes Based on [7,7-Dimethyl-9-(10-phenylanthracen-9-yl)-7H-Indeno[1,2-f] Isoquinoline] Derivatives

2020 ◽  
Vol 20 (11) ◽  
pp. 6648-6652
Author(s):  
Jinho Park ◽  
Beomsu Jang ◽  
Yu Ji Moon ◽  
Hakjun Lee ◽  
Young Kwan Kim ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Power Efficiency ◽  
Light Emitting Diodes ◽  
Blue Emission ◽  
Luminous Efficiency ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Deep Blue ◽  
Organic Light ◽  
Isoquinoline Derivatives

In this study, we synthesized and characterized two novel deep blue emitting materials based on indenoquinoline-substituted phenylanthracene derivatives. Multilayer organic light-emitting diodes were fabricated with the following sequence: indium-tin-oxide (ITO)/4,4′,4″-tris[2-naphthyl(phenyl)amino (2-TNATA)/4,4′-bis(N-N-naphthyl)-N-phenylamino) biphenyl (NPB)/Blue emitting material (1 or 2)/Bathophenanthroline (Bphen)/lithium quinolate (Liq)/Al. A device B using ‘7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-indeno[1,2-f] isoquinoline (2)’ as an emitter showed the efficient emission with the luminous efficiency, power efficiency, and external quantum efficiency of 2.30 cd/A, 1.02 lm/W, 2.94% at 20 mA/cm2, respectively. This device exhibited deep-blue emission with the Commission Internationale De LÉnclairage (CIE) coordinates of (0.16, 0.08) and λmax = 436 nm at 8.0 V.

Efficient organic light-emitting diodes based on iridium(III) complexes containing indolo[3,2,1-jk]carbazole derivatives with narrow emission bandwidths and low efficiency roll offs

2021 ◽  
Author(s):  
Xiang-Ji Liao ◽  
Jin-Jun Zhu ◽  
Li Yuan ◽  
Zhi-Ping Yan ◽  
Xu-Feng Luo ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Carbazole Derivatives ◽  
Highly Efficient ◽  
Organic Light ◽  
Low Efficiency ◽  
Narrow Emission

In this work, two cyclometalated ligands 2-(pyridin-2-yl)indolo[3,2,1-jk]carbazole (pyidcz) and 2-(4-(trifluoromethyl)pyridin-2-yl)indolo[3,2,1-jk]carbazole (tfpyidcz) using indolo[3,2,1-jk]carbazole unit were synthesized for highly efficient iridium(III) complexes (pyidcz)2Ir(tmd) and (tfpyidcz)2Ir(tmd) (tmd = 2,2,6,6-tetramethyl-3,5-heptanedione). The two Ir(III)...

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

Materials ◽  
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.

Four color stacked white organic light-emitting diodes utilizing the concept of triplet harvesting

2011 ◽  
Vol 1286 ◽  
Author(s):  
Th. C. Rosenow ◽  
S. Olthof ◽  
S. Reineke ◽  
B. Lüssem ◽  
K. Leo
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Light Sources ◽  
Emission Layer ◽  
Light Emitting ◽  
Organic Light ◽  
Blue Emitters ◽  
Color Rendering ◽  
Triplet Harvesting

ABSTRACTOrganic light-emitting diodes (OLEDs) are developing into a competitive alternative to conventional light sources. Nevertheless, OLEDs need further improvement in terms of efficiency and color rendering for lighting applications. Fluorescent blue emitters allow deep blue emission and high stability, while phosphorescent blue emitter still suffer from insufficient stability. The concept of triplet harvesting is the key for achieving internal quantum efficiencies up to 100 % and simultaneously benefiting from the advantages of fluorescent blue emitters. Here, we present a stacked OLED consisting of two units comprising four different emitters in total. The first unit takes advantage of the concept of triplet harvesting and combines the light emission of a fluorescent blue and a phosphorescent red emitter. The second unit emits light from a single emission layer consisting of a matrix doped with phosphorescent green and yellow emitters. With this approach, we reach white color coordinates close to the standard illuminant A and a color rendering index of above 75. The presented devices are characterized by high luminous efficacies of above 30 lm/W on standard glass substrates without outcoupling enhancement.

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