Author Affiliations
Abstract
1 Department of Green Energy & Semiconductor Engineering, Hoseo University, 513-3, 2nd Engineering Building, 20, Hoeo-ro beon-gil, baebang-eup, Asan-si, Chungcheongnam-do 31499, South Korea
2 Department of Engineering Physics, McMaster University, 1280 Main St W, Hamilton L8S 4L8, Canada
3 Department of Physics, Hong Kong Baptist University, Hong Kong, Kowloon Tong, Waterloo Road 224, China
The electroluminescent characteristics of blue organic light-emitting diodes (BOLEDs) fabricated with doped charge carrier transport layers are analyzed. The fluorescent blue dopant BCzVBi is doped in an emissive layer, hole transport layer (HTL) and electron transport layer (ETL), respectively, to optimize the probability of exciton generation in the BOLEDs. The luminance and luminous efficiency of BOLEDs made with BCzVBi-doped HTL and ETL increase by 22% and 17% from 11,683 cd/m2 at 8.5 V and 6.08 cd/A at 4.0 V to 14,264 cd/m2 at 8.5 V and 7.13 cd/A at 4.0 V while CIE coordinates of (0.15, 0.15) of both types of BOLEDs remained unchanged. The electron mobility of BCzVBi is estimated to be 1.02×10 5 cm2/Vs by TOF.
300.2140 Emission 300.6170 Spectra 230.3670 Light-emitting diodes Chinese Optics Letters
2016, 14(4): 043001
Author Affiliations
Abstract
1 Department of Green Energy and Semiconductor Engineering, Hoseo University, Asan 330-713, South Korea
2 Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S4L8, Canada
In this Letter, blue phosphorescence organic light-emitting diodes (PHOLEDs) employ structures for electron and/or hole confinement; 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene is used as a hole confinement layer and tris-(phenylpyrazole)iridium [Ir(ppz)3] is utilized for an electron confinement layer (ECL). The electrical and optical properties of the fabricated blue PHOLEDs with various carrier-confinement structures are analyzed. Structures with a large energy offset between the carrier confinement and emitting layers enhance the charge-carrier balance in the emitting region, resulting from the effective carrier confinement. The maximum external quantum efficiency of the blue PHOLEDs with the double-ECLs is 24.02% at 1500 cd/m2 and its luminous efficiency is 43.76 cd/A, which is 70.47% improved compared to the device without a carrier-confinement layer.
230.3670 Light-emitting diodes 230.0230 Optical devices 230.4170 Multilayers 230.4205 Multiple quantum well (MQW) modulators 230.5590 Quantum-well, -wire and -dot devices Chinese Optics Letters
2015, 13(3): 032301
Author Affiliations
Abstract
High-performance blue organic light-emitting diodes (OLEDs) are developed. A concept of using multiple-emissive layer (EML) configuration is adopted. In this letter, bis(2-methyl-8-quinolinolate)-4-(phenylphenolato)Al (BAlq) and 9,10-di(naphtha-2-yl)anthracene (ADN), which serve n- and p-type EMLs, respectively, are used to evaluate and demonstrate the multi-EML concept for blue OLEDs. The thickness effect of individual EMLs and the number of EMLs, e.g., triple and quadruple EML components, on the power efficiency of blue OLEDs are systematically investigated. To illustrate the point, the total thickness of the emissive region in different blue OLEDs are kept contact at 30 nm for comparison. The power efficiency of blue OLEDs with a quadruple EML structure of BAlq/ADN/BAlq/ADN is about 40% higher than that of blue OLEDs having a single EML unit. The Commission Internationale deL'eclairage color coordinates of multi-EML OLEDs have values that represent the average of blue emissions from individual EMLs of BAlq and ADN.
230.0230 Optical devices 230.3670 Light-emitting diodes 230.0250 Optoelectronics 160.4890 Organic materials 130.5990 Semiconductors Chinese Optics Letters
2014, 12(1): 012302
