A dithienyl benzotriazole-based poly(2,7-carbazole) for field-effect transistors and efficient light-emitting diodes

Abstract

In this work, a donor–acceptor type copolymer, poly[(N-9′-heptadecanyl-2,7-carbazole)-alt-(4,7-bis(2′-thienyl)-2-dodecyl-2,1,3-benzotriazole)] (PCDTBTz) is introduced for versatile applications in organic electronics. PCDTBTz exhibits excellent solubility, film-forming ability and morphological stability, along with charming optoelectronic properties. The solution processable OFET device displays typical p-type transporting characteristics with a moderate mobility up to 4.3 × 10⁻⁴ cm²/V·s upon thermal annealing at 80 °C, and PLEDs in the device structure of ITO/PEDOT:PSS (10 nm)/Poly-TPD (30 nm)/PCDTBTz (32 nm)/Alq₃ (40 nm)/Ca:Ag show a bright orange red emission with a maximum brightness of 13 655 cd/m² at 1607.9 mA/cm² and 12.6 V, and a maximum EL efficiency of 0.85 cd/A. All the results indicate that PCDTBTz is a promising candidate for optoelectronic materials used in both for polymer FETs and LEDs.