Synthesis, Characterization, and Electroluminescence of Polyfluorene Copolymers with Phenothiazine Derivative; Their Applications to High-Efficiency Red and White PLEDs

White electroluminescence from a single polymer system: phenothiazine derivatives as a red emissive dopant and polyfluorene as a blue host

Photo physical studies of organic light emitting copolymers and their ordered supramolecular self-assembly: tuning the electroluminescence properties with high efficient white light.

Phenothiazine-based bipolar green-emitters containing benzimidazole units: synthesis, photophysical and electroluminescence properties

A series of bipolar green emitters bearing hole-transporting phenothiazine and electron-transporting N-phenylbenzimidazole are synthesized and characterized by their photophysical, electrochemical and thermal properties.

Highly efficient red-emitting hybrid polymer light-emitting diodes via Förster resonance energy transfer based on homogeneous polymer blends with the same polyfluorene backbone

Highly efficient inverted-type red-emitting hybrid polymeric light-emitting diodes (HyPLEDs) were successfully demonstrated via Förster resonance energy transfer (FRET) and interfacial engineering of metal oxide with a cationic conjugated polyelectrolyte (CPE). Similarly structured green- and red-emissive polyfluorene copolymers, F8BT and F8TBT, were homogeneously blended as a FRET donor (host) and acceptor (dopant). A cationic polyfluorene-based CPE was also used as an interfacial layer for optimizing the charge injection/transport and improving the contact problem between the hydrophilic ZnO and hydrophobic polymer layer. A long Förster radius (R0 = 5.32 nm) and high FRET efficiency (~80%) was calculated due to the almost-perfect spectral overlap between the emission of F8BT and the absorption of F8TBT. A HyPLED containing 2 wt % F8TBT showed a pure red emission (λmax = 640 nm) with a CIE coordinate of (0.62, 0.38), a maximum luminance of 26 400 cd/m(2) (at 12.8 V), a luminous efficiency of 7.14 cd/A (at 12.8 V), and a power efficiency of 1.75 lm/W (at 12.8 V). Our FRET-based HyPLED realized the one of the highest luminous efficiency values for pure red-emitting fluorescent polymeric light-emitting diodes reported so far.