Driving characteristics of poly(N-vinylcarbazole) and 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3-4-oxadiazole-based polymer light emitting diodes

• Published in: Electronic materials letters 2013, 9(5), , pp.663-668
• Main Authors: Lee, Dae-Yeol, Lee, Myong-Hoon, Lee, Chan-Jae, Park, Sung-Kyu
• Format: Article
• Language: English
• Subjects: Carrier transport; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Devices; Dopants; Electroluminescence; Light-emitting diodes; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials; Photodiodes; Polyvinyl carbazole; Transport; 전자/정보통신공학
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-013-3061-y

We studied the driving characteristics of Poly(N-vinylcarbazole) (PVK)-based polymer light emitting diodes (PLEDs) by incorporating various 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3-4-oxadiazole (PBD) concentrations. PVK (M n =25,000∼50,000 g/mol) and tris(2-(4-tolyl)phenylpyridine)iridium (Ir(mppy) 3 ) were used as the host and dopant materials, respectively. The transient electroluminescence (EL) of the PLED measurement was used to analyze the characteristics of the carrier transport by synchronizing the DC-pulse generator (10 V, 70 Hz) and photodiode. Among the fabricated PLEDs including those with different PBD concentrations from 0% to 60%, the devices with 60% PBD concentration showed the highest efficiency (15.5 cd/A) at 1000 cd/m 2 . By increasing the PBD concentration, a shorter rising time of the PLEDs was achieved possibly due to improved transport behavior of the electrons by the PBD incorporation. This result is well agreement with the increased device efficiency by increasing the PBD concentration, which shows that the transient EL measurement can be a good method for analyzing PLED performance and charge balancing.