Synthesis and luminescent properties of two Schiff-base boron complexes

Schiff bases N,N′-o-phenylenebis (salicylideneimine) (H2L1), N,N′-p-phenylenebis (salicylideneimine) (H2L2) and their corresponding boron complexes (BF2)2L1, (BF2)2L2 were synthesized, respectively. The two boron complexes have been characterized by 1H NMR, mass spectrometry and elemental analysis, while the luminescent properties of them were investigated with UV–VIS spectroscopy and photoluminescence spectroscopy. Then the three-layer devices [ITO/NPB (60 nm)/(BF2)2L1 (50 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm)] (device I) and [ITO/NPB (60 nm)/(BF2)2L2 (50 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm)] (device II) were fabricated by vacuum deposition. These two devices both exhibited blue green emission at 500 nm, but showed different luminances and efficiencies.