Synthesis, Characterisation, and Electroluminescence Properties of N‐Coumarin Derivatives Containing Peripheral Triphenylamine

A series of N‐coumarin derivatives, namely CThnT and CThnCT (n = 1–2), containing triphenylamine or triphenylamine‐substituted carbazole as substituent were synthesised, and their structures were confirmed by MALDI‐TOF MS, and NMR and IR spectroscopy. Their optical, physical and electroluminescence properties as non‐doped solution‐processed light‐emitters for OLEDs were investigated. DSC, TGA, AFM and PL spectra revealed their good film‐forming properties, high thermal and morphological stability, and good photoluminescence characteristics. The double‐layer solution‐processed OLEDs (ITO/PEDOT:PSS/EML/BCP/LiF:Al) fabricated using CThnT and CThnCT as the emissive layer and BCP as the electron‐transporting and hole‐blocking layer, exhibited stable green to orange electroluminescence (λEL = 536–592 nm) with turn‐on voltages of 2.7–2.9 V and maximum luminance efficiencies up to 3.94 cd A–1 at 17.6 mA cm–2 (maximum power efficiency of 1.62 lm W–1).