Development of efficient solution-processed red phosphorescent organic light-emitting diodes using carrier transport materials

• Published in: Synthetic metals Vol. 160; no. 15; pp. 1623 - 1626
• Main Authors: Song, Myungkwan, Park, Jin Su, Kim, Chul-Hyun, Kim, Jang Soo, Gal, Yeong-Soon, Lee, Jae Wook, Jin, Sung-Ho
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2010; Elsevier
• Subjects: Applied sciences; Carrier transport; Carrier-transporting material; Devices; Electroluminescence; Electronics; Exact sciences and technology; Light-emitting diodes; Luminance; Optoelectronic devices; PhOLEDs; Phosphorescent; Polyvinyl carbazole; Power efficiency; Red; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solution-process; Spectra; Transporting; Red; PhOLEDs; Solution-process; Phosphorescent; Carrier-transporting material; Performance evaluation; Polymer blends; Red light; Doped materials; Electroluminescence; Carbazole(vinyl) polymer; Optimization; Transport process; Luminance; Optoelectronic device; Organic light emitting diodes; Oxadiazole derivatives; Acetylacetone derivatives; Doped polymer; Phosphorescence; Iridium; Growth from solution; Organic electronics
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2010.05.030

We report on efficient solution-processed red emissive phosphorescent organic light-emitting diodes (PhOLEDs) employing bis[9-ethyl-3-(4-phenylquinolin-2-yl)-9H-carbazolato- N, C 2′]iridium acetylacetonate (Et-Cvz-PhQ) 2Ir(acac) and bis[9-(2-(2-methoxyethoxy)ethyl)-3-(4-phenylquinolin-2-yl)-9H-carbazolato- N, C 2′]iridium acetylacetonate (EO-Cvz-PhQ) 2Ir(acac) doped into polymer host PVK, blended with electron transporting material OXD-7, and optimized concentration of carrier-transporting material TPD. The optimized PhOLEDs doped with 16 wt% carrier-transporting material shows a maximum luminance efficiency and power efficiency of 4.66 cd/A and 1.22 lm/W, which were increased by 40% and 20%, respectively, compared with that of reference device. The electroluminescence (EL) spectra exhibited the characteristic spectrum of (Et-Cvz-PhQ) 2Ir(acac) and (EO-Cvz-PhQ) 2Ir(acac) with its maximum at 630 nm and CIE (Commission International de L’Eclairage) coordinate of (0.66, 0.33).