Efficient bifunctional materials based on pyrene- and triphenylamine-functionalized dendrimers for electroluminescent devices

Abstract

To realize highly efficient bifunctional blue-light emitting and hole-transporting materials for OLEDs, a series of pyrene- and triphenylamine-peripheral functionalized carbazole dendrimers, namely G1PYR, G2PYR, G1TPA and G2TPA, were designed, synthesized and characterized. Especially, G2PYR having four pyrene units substituted on the 2^nd generation carbazole dendritic scaffold exhibited a strong blue emission with high T_g amorphous and good film-forming properties. Simple structured blue OLED (λ_EL = 463 nm) using G2PYR as emissive layer and Alq3-based green OLED (λ_EL = 512 nm) using G2PYR as hole-transporting layer with high luminance efficiencies (η) and low turn-on voltages (V_on) of 5.89 cd A⁻¹ and 3.1 V, and 5.15 cd A⁻¹ and 2.6 V were attained, respectively.