New spirobifluorene-based hole-transporting semiconductors for electroluminescent devices

2014 ◽  
Vol 2 (38) ◽  
pp. 8098-8104 ◽  
Author(s):  
Özlem Usluer

A series of spirofluorene-centered, carbazole and thiophene-linked molecules as hole transport materials in organic light-emitting diodes.

1995 ◽  
Vol 413 ◽  
Author(s):  
S. Joshua Jacobs ◽  
Timothy P. Pollagi ◽  
Michael B. Sinclair ◽  
Rodger D. Scurlock ◽  
Peter R. Ogilby

ABSTRACTWe have investigated the performance of a class of heterocycles, 5,10-dihetera- 5,10-dihydroindeno[3,2b]indenes, as hole transport agents in simple double heterostructure organic light-emitting diodes with tris(8-hydroxyquinoline)aluminum (Alq). The best of these materials, 5,10-dihydroindolo[3,2b]indole, yields devices with luminance and lifetimes comparable to those obtained using N,N′-di-(3-methylphenyl)-N,N′- diphenyl-4,4′-diaminobiphenyl (TPD) as a hole transporting material.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria Vasilopoulou ◽  
Abd. Rashid bin Mohd Yusoff ◽  
Matyas Daboczi ◽  
Julio Conforto ◽  
Anderson Emanuel Ximim Gavim ◽  
...  

AbstractBlue organic light-emitting diodes require high triplet interlayer materials, which induce large energetic barriers at the interfaces resulting in high device voltages and reduced efficiencies. Here, we alleviate this issue by designing a low triplet energy hole transporting interlayer with high mobility, combined with an interface exciplex that confines excitons at the emissive layer/electron transporting material interface. As a result, blue thermally activated delay fluorescent organic light-emitting diodes with a below-bandgap turn-on voltage of 2.5 V and an external quantum efficiency (EQE) of 41.2% were successfully fabricated. These devices also showed suppressed efficiency roll-off maintaining an EQE of 34.8% at 1000 cd m−2. Our approach paves the way for further progress through exploring alternative device engineering approaches instead of only focusing on the demanding synthesis of organic compounds with complex structures.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 554
Author(s):  
Taeshik Earmme

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.


2017 ◽  
Vol 5 (8) ◽  
pp. 2066-2073 ◽  
Author(s):  
Rongzhen Cui ◽  
Weiqiang Liu ◽  
Liang Zhou ◽  
Xuesen Zhao ◽  
Yunlong Jiang ◽  
...  

High performance sensitized organic light-emitting diodes with high color purity were obtained by utilizing terbium or gadolinium complexes as sensitizers.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Nang Dinh ◽  
Do Ngoc Chung ◽  
Tran Thi Thao ◽  
David Hui

Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO2nanoparticles for the hole transport layer and emission layer were prepared, respectively, for organic emitting diodes (OLEDs). The composite of MEH-PPV+nc-TiO2was used for organic solar cells (OSCs). The characterization of these nanocomposites and devices showed that electrical (I-Vcharacteristics) and spectroscopic (photoluminescent) properties of conjugate polymers were enhanced by the incorporation of nc-TiO2in the polymers. The organic light emitting diodes made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the organic solar cells made from MEH-PPV+nc-TiO2composite, a fill factor reached a value of about 0.34. Under illumination by light with a power density of 50 mW/cm2, the photoelectrical conversion efficiency was about 0.15% corresponding to an open circuit voltageVoc= 0.126 V and a shortcut circuit current densityJsc= 1.18 mA/cm2.


2007 ◽  
Vol 91 (1) ◽  
pp. 011113 ◽  
Author(s):  
Dong-Seok Leem ◽  
Hyung-Dol Park ◽  
Jae-Wook Kang ◽  
Jae-Hyun Lee ◽  
Ji Whan Kim ◽  
...  

2017 ◽  
Vol 5 (38) ◽  
pp. 10029-10038 ◽  
Author(s):  
Woosum Cho ◽  
Ganguri Sarada ◽  
Athithan Maheshwaran ◽  
Yeong-Soon Gal ◽  
Yeonsig Nam ◽  
...  

Linking the hole transporting/electron transporting functional moieties to the Ir(iii) complex is a key strategy to improve performance of PhOLEDs.


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