Near-IR electromer emission from new ambipolar carbazole containing phosphorescent dendrimer based organic light emitting diode

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• 作者：Hyong-Jun Kim ; Myeong-Jun Kim ; Hyung-Dol Park ; Jae-Hyun Lee ; Si Tae Noh ; Young-Chul Lee ; Jang-Joo Kim
• 关键词：Phosphorescent OLED ; Electromer ; Carbazole ; Near-IR ; Solution process
• 刊名：Synthetic Metals
• 出版年：2010
• 出版时间：September 2010
• 年：2010
• 卷：160
• 期：17-18
• 页码：1994-1999
• 全文大小：396 K

文摘

The solution process is more suitable for large-sized OLED in terms of small material usage and no need for fine mask patterning technique. Among soluble materials, dendrimers are acknowledged as a new class of emissive OLED materials that can carry both the emissive chromophore and the charge transporting moiety simultaneously. Here, we report on a new Ir(III)-based dendrimer and an efficient single emission layer OLED device by spin-coating the dendrimer itself on PEDOT:PSS polymer. This dendrimer carries a pair of carbazole functional groups on the pyridine side and a fluorinated phenyl on the other side of the Ir(ppy)₃ ligand. The latter functional group acts as an electron transporting material and the former as a host and hole-transporting material. The dendrimer device has a green emission at 540 nm with current efficiency as high as 25 Cd/A. Interestingly, we have found that the two neighboring carbazole form the electromer under the applied electrical current and, thus, that the EL device shows new near-IR emission over 720 nm.