Highly Efficient Orange and Warm White Phosphorescent OLEDs Based on a Host Material with a Carbazole–Fluorenyl Hybrid |
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| Authors: | Xiaoyang Du Yun Huang Dr Silu Tao Xiaoxia Yang Chuan Wu Huaixin Wei Dr Mei‐Yee Chan Dr Vivian Wing‐Wah Yam Prof Chun‐Sing Lee |
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| Institution: | 1. School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China), Fax: (+86)?28‐83201745;2. Center of Super‐Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Science, City University of Hong Kong, Hong Kong Special Administrative Region (China), Fax: (+852)?27847826;3. Department of Chemistry, The University of Hong Kong, Hong Kong Special Administrative Region (China) |
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| Abstract: | A new carbazole–fluorenyl hybrid compound, 3,3′(2,7‐di(naphthaline‐2‐yl)‐9H‐fluorene‐9,9‐diyl)bis(9‐phenyl‐9H‐carbazole) (NFBC) was synthesized and characterized. The compound exhibits blue‐violet emission both in solution and in film, with peaks centered at 404 and 420 nm. In addition to the application as a blue emitter, NFBC is demonstrated to be a good host for phosphorescent dopants. By doping Ir(2‐phq)3 in NFBC, a highly efficient orange organic light‐emitting diode (OLED) with a maximum efficiency of 32 cd A?1 (26.5 Lm W?1) was obtained. Unlike most phosphorescent OLEDs, the device prepared in our study shows little efficiency roll‐off at high brightness and maintains current efficiencies of 31.9 and 26.8 cd A?1 at a luminance of 1000 and 10 000 cd m?2, respectively. By using NFBC simultaneously as a blue fluorescence emitter and as a host for a phosphorescent dopant, a warm white OLED with a maximum efficiency of 22.9 Lm W?1 (21.9 cd A?1) was also obtained. |
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| Keywords: | blue fluorescent host doping fluorescence OLEDs phosphorescence warm white emission |
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