Both Luminous Efficiency and Lifetime Enhancement in Blue Fluorescence OLEDs by Modifying Molecular Structure of Hole Transporting Material

2011 ◽  
Vol 1286 ◽  
Author(s):  
Yoonhyun Kwak ◽  
Sun-Young Lee ◽  
Hye-In Jeong ◽  
Dae-Yup Shin ◽  
Young-Woo Song ◽  
...  
Keyword(s):  
Energy Levels ◽  
Luminous Efficiency ◽  
Coupling Reactions ◽  
Blue Fluorescence ◽  
Lumo Energy ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Hole Transporting ◽  
Palladium Catalyzed ◽  
Hole Transporting Material

ABSTRACTBoth luminous efficiency and lifetime in blue fluorescence organic light emitting devices (OLEDs) have been improved by modified HTMs with higher LUMO energy levels. The LUMO energy levels of HTM were increased by modifying substituent in HTM molecules. Two HTMs containing ortho and meta biphenyl substituent and one HTM containing thiophene substituent were synthesized via palladium catalyzed amine coupling reactions to compare with a para biphenyl substituent HTM-1 as a standard molecule. According to TDDFT calculations, these three modified HTMs showed 0.05-0.15 eV higher LUMO energy levels compared to the para biphenyl substituent HTM-1. The luminous efficiency and the lifetime (LT90) of OLEDs using HTM-2 at 500 cd/m2 have been enhanced up to 20 % and 52 %, respectively, compared to the standard device using HTM-1.

A High Tg Carbazole-Based Hole-Transporting Material for Organic Light-Emitting Devices

2005 ◽  
Vol 17 (5) ◽  
pp. 1208-1212 ◽  
Author(s):  
Jiuyan Li ◽  
Di Liu ◽  
Yanqing Li ◽  
Chun-Sing Lee ◽  
Hoi-Lun Kwong ◽  
...  
Keyword(s):  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Hole Transporting ◽  
Organic Light Emitting Devices ◽  
Hole Transporting Material

Highly efficient blue organic light-emitting diodes using DPASN quantum well structure

2013 ◽  
Vol 1567 ◽  
Author(s):  
Ju-An Yoon ◽  
You-Hyun Kim ◽  
Nam Ho Kim ◽  
Seung Il Yoo ◽  
Sang Youn Lee ◽  
...  
Keyword(s):  
Quantum Well ◽  
Energy Levels ◽  
Luminous Efficiency ◽  
Organic Light Emitting Diodes ◽  
Electron Recombination ◽  
Lumo Energy ◽  
Light Emitting ◽  
Quantum Well Structure ◽  
Organic Light ◽  
Homo Lumo

ABSTRACTIn this study, we fabricated blue OLEDs with quantum well structure (QWS) using four different blue emissive materials such as DPVBi, ADN and DPASN, and BAlq as QWS material. Conventional QWS blue OLEDs used to be composed of emissive layer and charge blocking layer with lower HOMO-LUMO energy level, but we designed triple emitting layer for more significant hole-electron recombination in EML and a wider region of exciton generation as forming QWS spontaneously. The structure of triple emitting layered blue OLED is ITO / NPB(700 Å) / X(100 Å) / BAlq(100 Å) /X (100 Å) / Bphen(300 Å) / Liq(20 Å) / Al(1200 Å) (X= DPVBi, ADN, DPASN). HOMO-LUMO energy levels of DPVBi, ADN, DPASN and BAlq were 2.8-5.9, 2.6-5.6, 2.3-5.2 and 2.9-5.9 eV, respectively. The maximum luminous efficiency was 5.32 cd/A at 3.5 V in a blue OLED with DPASN / BAlq / DPASN QWS.

HighTgTriphenylamine-Based Starburst Hole-Transporting Material for Organic Light-Emitting Devices

2007 ◽  
Vol 19 (24) ◽  
pp. 5851-5855 ◽  
Author(s):  
Qing-Xiao Tong ◽  
Shiu-Lun Lai ◽  
Mei-Yee Chan ◽  
Ka-Ho Lai ◽  
Jian-Xin Tang ◽  
...  
Keyword(s):  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Hole Transporting ◽  
Organic Light Emitting Devices ◽  
Hole Transporting Material

Spectroelectrochemical Study of the Formation of Radical cations of 4,4’-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl as a Hole Transport Semiconductor Material

2011 ◽  
Vol 1286 ◽  
Author(s):  
Sharavsambuu Baasanjav ◽  
Gendensvren Bolormaa ◽  
Batjargal Naranbileg ◽  
Munkhbat Battulga ◽  
Chimed Ganzorig
Keyword(s):  
Radical Cations ◽  
Band Gap Energy ◽  
Hole Transport ◽  
Emission Region ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Quenching Process ◽  
Hole Transporting ◽  
Uv Visible ◽  
Hole Transporting Material

ABSTRACTSpectroelectrochemical study on a new absorption band of radical cations of 4,4’-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl (α-NPD) as an electron-donor hole-transporting material used in organic electronics is reported in this work. UV-visible spectroscopic and cyclic voltammetric properties for α-NPD in solution are also examined. We find that the results are attributed to quenching process for blue fluorescence from α-NPD by excess α-NPD+ radical cations accumulated in the emission region in the organic light-emitting devices related to a relatively large overlap between the fluorescence spectrum of α-NPD and the absorption spectrum of α-NPD+ radical cations. The band gap energy for α-NPD is calculated from the UV-visible spectroscopic data.

SYNTHESIS AND CHARACTERIZATION OF ALTERNATING COPOLYMERS CONTAINING CARBAZOLE AND ANILINE MOIETIES

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3981-3986
Author(s):  
HUI WANG ◽  
DONG-HEE HAN ◽  
SEUNG HYUN CHANG ◽  
JEONG-TAK RYU ◽  
YOUNGHWAN KWON
Keyword(s):  
Blue Emission ◽  
Electrochemical Characteristics ◽  
Host Matrix ◽  
Excellent Thermal Stability ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Molecular Weights ◽  
Alternating Copolymers ◽  
Hole Transporting ◽  
Palladium Catalyzed

Four different types of alternating copolymers, named as poly(N-(2-ethylhexyl)-3,6-dibromo-carbazole-alt-aniline) (P1), poly(3,6-dibromo-carbazole-alt-aniline) (P2), poly(N-(3,5-dibromo-methylene-phenyl)-carbazole-alt-aniline) (P3) and poly(N-[4-(2-ethylhexyloxyl)-3,5-dibromomethylene-phenyl]-carbazole-alt-aniline) (P4) were successfully synthesized by palladium-catalyzed polycondensation of corresponding carbazole-containing dibrominated compounds and an aniline. These resulting polymers exhibited good solubility in normal organic solvents and showed relatively high molecular weights. Excellent thermal stability of the polymers was observed from TGA, showing less than 8% of weight loss on heating to 350°C under N 2 atmosphere. From UV-Vis absorption and photoluminescence spectra of these solution-processable polymers, it was observed that λ max,UV was in the range of 308 – 352 nm and λ max,PL was in the blue emission range of 450 – 463 nm. Electrochemical characteristics of these alternating copolymers were investigated to prove the potential in application for blue-emitting host matrix and hole-transporting layer in polymer light-emitting devices.

Inkjet printing high luminance phosphorescent OLED based on m-MTDATA:TPBi host

2019 ◽  
Vol 33 (12) ◽  
pp. 1950149 ◽  
Author(s):  
Xing Xing ◽  
Tong Lin ◽  
Yong-Xu Hu ◽  
Yu-Ling Sun ◽  
Wan-Ying Mu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
High Performance ◽  
High Luminance ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Single Host ◽  
Hole Transporting ◽  
Phosphorescent Material ◽  
Hole Transporting Material ◽  
Balance Charge

In organic light-emitting devices (OLEDs), the high performance of devices depends on balanced charge transfer in emitting layer (EML). However, the balance charge transfer is hard to achieve in the single host material-based EML. In this work, a high luminance co-host based OLEDs is printed. In detail, green phosphorescent material tris[2-(p-tolyl)pyridine]iridium(III) [Formula: see text] is used as dopant, and a hole-transporting material [Formula: see text]-tris[3-methy-lphenyl(phenyl)amino]-triphenylamine (m-MTDATA) blended with an electron-transporting material 1,3,5-tris(phenyl-2-benzimidazolyl)-benzene (TPBi) as co-host. As a result, the optimized printing co-host OLEDs with 10 wt.% [Formula: see text] shows a maximum luminance of [Formula: see text], which is much higher than the CDBP counterpart.

Influence of hole transporting material on device performance in organic light-emitting diode

2000 ◽  
Vol 363 (1-2) ◽  
pp. 290-293 ◽  
Author(s):  
Shizuo Tokito ◽  
Koji Noda ◽  
Kou Shimada ◽  
Shin-ichiro Inoue ◽  
Makoto Kimura ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Device Performance ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Hole Transporting ◽  
Hole Transporting Material

Improve the Efficiency of White Organic Light-Emitting Devices Using Double-Doped System

2010 ◽  
Vol 152-153 ◽  
pp. 687-690
Author(s):  
Gui Ying Ding ◽  
Wen Long Jiang ◽  
Guang De Wang ◽  
Qiang Han ◽  
Xi Chang
Keyword(s):  
Current Efficiency ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Maximum Current ◽  
Hole Transporting ◽  
White Oleds ◽  
Organic Light Emitting Devices ◽  
20 Nm ◽  
White Oled

The doped and non-doped white Organic light-emitting devices (OLEDs) were fabricated, using strong yellow emitting and hole-transporting ability of TPAHQZn. When the white OLED is a double-doped structure, greatly enhanced the efficiency of the device. The double-doped white device were fabricated as follows: ITO/2T-NATA (17 nm)/ CBP: 30% TPAHQZn: 8% Ir(ppy)3 (25 nm)/ NPBX (15 nm)/BCP(8nm)/TPBi: 10% Ir(ppy)3 (15nm)/Alq3 (20 nm)/LiF (1.3 nm)/Al. The double-doped white OLEDs were obtained with Commission International de L’Eclairage coordinates of (0.29,0.28) at 17 V, the maximum current efficiency increaed four times that double-doped white device of 4.12cd/A(8V) than non-doped of 1.03 cd/A (10V) .

Small molecular hole-transporting and emitting materials for hole-only green organic light-emitting devices

2016 ◽  
Vol 131 ◽  
pp. 41-48 ◽  
Author(s):  
Xicheng Liu ◽  
Junfei Liang ◽  
Jing You ◽  
Lei Ying ◽  
Yin Xiao ◽  
...  
Keyword(s):  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Hole Transporting ◽  
Organic Light Emitting Devices
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