MeS2B(p-4,4′-biphenyl-NPh(1-naphthyl)):: A multifunctional molecule for electroluminescent devices

Mes(2)B(p-4,4'-biphenyl-NPh(1-naphthyl)), (BNPB) a novel luminescent molecule that contains part of the well-known NPB functionality (NPB = N,N'-di-1-naphthyl-N,N'-diphenylbenzidine) and a three-coordinate boron center has been synthesized. BNPB is a bright blue emitter with lambda(max) (emission) = 452 nm and a photoluminescent quantum yield of 95% in solution and 31% in the solid state. BNPB is an amorphous material and forms films readily via either solution casting or vacuum vapor deposition. A single layer EL device A with the device structure of ITO/BNPB/LiF/Al, two double-layer EL devices B and C with the device structure of ITO/NPB/BNPB/Ag for B and ITO/BNPB/Alq(3)/LiF/Al for C, and a triple-layer device D with the structure of ITO/NPB/BNPB/Alq(3)/LiF/Al have been fabricated and their performance has been evaluated. Device A produces a weak blue electroluminescence (EL). Device B produces a bright blue EL, identical to that of device A. Device C produces a green EL, typical of Alq(3). Device D produces a broadband whitish-blue EL attributable to dual emission from the BNPB zone and the Alq(3) zone. Devices A-D demonstrate that BNPB is capable of transporting both holes and electrons in addition to being a blue emitter for EL devices.