Highly Efficient Red Phosphorescent OLEDs based on Non‐Conjugated Silicon‐Cored Spirobifluorene Derivative Doped with Ir‐Complexes |
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Authors: | Yi‐Yeol Lyu Jeonghun Kwak Woo Sung Jeon Younghun Byun Hyo Sug Lee Doseok Kim Changhee Lee Kookheon Char |
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Affiliation: | 1. Samsung Advanced Institute of Technology, Mt. 14‐1, Nongseo‐Ri Giheung‐Eup, Yongin‐Si, Gyeonggi‐Do 449‐712 (Korea);2. School of Electrical Engineering and Computer Science Inter‐University Semiconductor Research Center Seoul National University 599 Gwanakro, Gwanak‐ku, Seoul 151‐742 (Korea);3. Department of Physics, Sogang University 1 Sinsoo, Mapo‐gu, Seoul 100‐611 (Korea);4. School of Chemical and Biological Engineering NANO Systems Institute‐National Core Research Center Seoul National University 599 Gwanakro, Gwanak‐ku, Seoul 151‐742 (Korea) |
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Abstract: | A novel host material containing silicon‐cored spirobifluorene derivative (SBP‐TS‐PSB), is designed, synthesized, and characterized for red phosphorescent organic light‐emitting diodes (OLEDs). The SBP‐TS‐PSB has excellent thermal and morphological stabilities and exhibits high electroluminescence (EL) efficiency as a host for the red phosphorescent OLEDs. The electrophosphorescence properties of the devices using SBP‐TS‐PSB as the host and red phosphorescent iridium (III) complexes as the emitter are investigated and these devices exhibit higher EL performances compared with the reference devices with 4,4′‐N,N′‐dicarbazole‐biphenyl (CBP) as a host material; for example, a (piq)2Ir(acac)‐doped SBP‐TS‐PSB device shows maximum external quantum efficiency of ηext = 14.6%, power efficiency of 10.3 lm W?1 and Commission International de L'Eclairage color coordinates (0.68, 0.32) at J = 1.5 mA cm?2, while the device with the CBP host shows maximum ηext = 12.1%. These high performances can be mainly explained by efficient triplet energy transfer from the host to the guests and improved charge balance attributable to the bipolar characteristics of the spirobifluorene group. |
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Keywords: | electrodes electroluminescence light‐emitting diodes silicon |
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