Synthesis and Application of Benzodithiophene Derivatives Based D′A-D-A-D′ Red Emitters

Abstract Organic red emitters have shown great prospective applications in full-color displays fluorescent probes and photothermal therapy et al.However it is still challenging for organic emitters that exhibited intense red emission with a maximum emission ( em ) above 680 nm in solid state.In this work two D'-A-D-A-D' molecules with a benzodithiophene derivative core donor (D) a benzothiadiazole acceptor (A) and a N-phenyl-2-naphthyl amine derivative peripheral electron donor (D') but differing in fluorine-free D' (RH) and fluorinated D' (RF) were synthesized.Their chemical structures were characterized and confirmed by nuclear magnetic resonance spectrosco py and mass spectroscopy.It is found both of them presented em > 700 nm in solid films.Meanwhile RF showed a more pronounced aggregation-induced emission enhancement effect and a higher photoluminescence quantum yield than those of RH attributed to the fluorination induced a larger dipole moment and more twisted structure of RF.LED devices based on RH and RF doped PMMA as colour conversion layers were fabricated respectively.The maximum brightness of RF based device reaches 2. 5-fold of RH based device at a 3. 8 V work voltage and its CIE coordinates