Novel Bis[5-(fluoren-2-yl)thiophen-2-yl]benzothiadiazole End-Capped with Carbazole Dendrons as Highly Efficient Solution-Processed Nondoped Red Emitters for Organic Light-Emitting Diodes

作者：Prachumrak Narid; Pojanasopa Sirintra; Namuangruk Supawadee; Kaewin Tinnagon; Jungsuttiwong Siri****; Sudyoadsuk Taweesak; Promarak Vinich^*

来源：ACS Applied Materials & Interfaces, 2013, 5(17): 8694-8703.

DOI：10.1021/am402349v

• organic light-emitting diode
• nondoped red emitter
• dendrimer
• carbazole dendron
• benzothiadiazole
• fluorene

A series of novel red-emitting bis[5-(fluoren-2-yl)thiophen-2-yl]benzothiadiazole-cored dendrimers containing carbazole dendrons up to the third generation are synthesized. Their photophysical, thermal, electrochemical, and electroluminescent properties as nondoped solution-processed red light-emitters for OLEDs are investigated. By using carbazole dendrons as the end caps, we are able to reduce the crystallization and retain the high emissive ability of a planar fluorescent core in the solid state as well as improve the thermal stability of the material. These dendrimers show a bright-red fluorescence and can form morphologically stable amorphous thin films with glass-transition temperatures as high as 283 degrees C. Simple structured solution-processed OLEDs using these materials as hole-transporting nondoped emitters and BCP as the hole-blocking layer emit a stable red color around 622-645 nm, with high luminance efficiencies (up to 4.80 cd A(-1) at 1.2 mA cm(-2)) and CIE coordinates of (0.65, 0.33), which are close to the pure red color.

• 出版日期2013-9-11