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

作者：Kim Hyong Jun^*; Kim Myeong Jun; Park Hyung Dol; Lee Jae Hyun; Noh Si Tae; Lee Young Chul; Kim Jang Joo

来源：Synthetic Metals, 2010, 160(17-18): 1994-1999.

DOI：10.1016/j.synthmet.2010.07.024

• Phosphorescent OLED
• Electromer
• Carbazole
• Near-IR
• Solution process

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.

• 出版日期2010-9