title: 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.
abstract: 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 °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.
authors: Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University , Ubon Ratchathani, 34190 Thailand.
authors: Narid
authors: N
authors: Prachumrak
authors: Sirintra
authors: S
authors: Pojanasopa
authors: Supawadee
authors: S
authors: Namuangruk
authors: Tinnagon
authors: T
authors: Kaewin
authors: Siriporn
authors: S
authors: Jungsuttiwong
authors: Taweesak
authors: T
authors: Sudyoadsuk
authors: Vinich
authors: V
authors: Promarak