Bis(1-phenyl-1H-benzo[d]imidazole)phenylphosphine oxide interlayer for effective hole blocking in efficient phosphorescent organic light emitting diodes based on widely used charge transporting layers

• Published in: Synthetic metals Vol. 190; pp. 39 - 43
• Main Authors: Cheon, Ye Rim, Yun, Hui-Jun, Thangaraju, Kuppusamy, Kim, Yun-Hi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2014; Elsevier
• Subjects: Applied sciences; Effective hole-blocking interlayer; Electronics; Exact sciences and technology; Green-emitting Ir(ppy)3 dopant; Higher efficiency; Optoelectronic devices; Phosphorescent OLEDs; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Higher efficiency; Effective hole-blocking interlayer; Phosphorescent OLEDs; Green-emitting Ir(ppy)3 dopant; Interfacial layer; Iridium complex; Electroluminescence; Aluminium complex; Experimental study; Quantum yield; Naphthalene derivatives; Tertiary phosphine oxide; Benzimidazole derivatives; Biphenyl derivatives; Doped compound; dopant; Organic light emitting diodes; ITO layers; Manufacturing; Green-emitting Ir(ppy); Vacuum deposition
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2014.01.018

•PHOLEDs based on Ir(ppy)3 emit at 512nm with CIE color coordinates of (0.30, 0.59).•BIPO with deep HOMO and higher electron transport property effectively blocks the holes.•ETL type BIPO interlayer improves the charge balance in the EML of the device.•PHOLED using NPB, TcTa, BIPO HBL, and Alq3 shows the maximum luminance of 75,080cd/m2.•It exhibits the higher device efficiencies of 44.37cd/A, 14.42% and 14.67lm/W. We have developed the efficient phosphorescent organic light emitting diodes (PHOLEDs) based on green-emitting fac-tris(2-phenylpyridine)iridium [Ir(ppy)3] dopant with widely used charge transporting layers. PHOLEDs show the electroluminescence emission from the dopant emitter at 512nm with CIE color coordinates of (0.30, 0.59). We investigated the roll of a 10-nm-thick electron-transporting type bis(1-phenyl-1H-benzo[d]imidazole)-phenylphosphine oxide (BIPO) interlayer in the device efficiencies. BIPO with the deep HOMO energy level and higher electron transporting ability effectively blocks the holes from EML to ETL and improves the charge balance in the EML of the device, resulting in the higher device external quantum efficiency of 14.42%, current efficiency of 44.37cd/A, and power efficiency of 14.67lm/W with a maximum luminance of 75,080cd/m2. The results show that the BIPO interlayer can be very much useful for the efficient low-cost device fabrication.