Carbazole-functionalized dibenzo[g,p]chrysene derivatives: Synthesis and luminescence properties

Two carbazole-functionalized dibenzo[g,p]chrysene (DBC) derivatives (DBC-1 and DBC-2) were synthesized by Buchwald-Hartwig cross-coupling reaction between 3,11-dibromodibenzo[g,p]chrysene and 3,6-di-tert-butyl- carbazole or 3,3 '',6,6 ''-tetra-tert-butyl-9 ' H-9,3 ':6 ',9 ''-tercarbazole, and characterized by NMR (1H and 13C) and high resolution mass spectrometry. Their photophysical and electrochemical properties as well as thermal stabilities were investigated systematically. These compounds showed intense blue emission with photoluminescence quantum yield of 44 % and 75 % in toluene solution, respectively. By using 1,3-bis(N-carbazolyl)benzene (mCP) as the host material, the doped devices with a device structure of ITO/PEDOT:PSS (30 nm)/mCP:DBC derivative (x wt%) (25 nm)/TPBi (35 nm)/Liq (2 nm)/Al (150 nm) were fabricated to characterize their electroluminescent properties, in which the emitting layer (mCP:DBC derivative) was prepared by solution-processed method. Their devices exhibited deep-blue emission with a maximum external quantum efficiencies (EQEmax) of 1.01 % for DBC-1 and 1.90 % for DBC-2.