Synthesis and properties of 2,3,6,7-tetraarylbenzo[1,2-b:4,5-b′]difurans as hole-transporting material

A new zinc-based annulation method produced regioselectively a variety of 2,3,6,7-tetraarylbenzo[1,2-b :4,5-b ']difurans in good yields. The organic electroluminescent devices using these tetraarylbenzodifurans as hole-transporting materials showed better performance than those using alpha-NPD, the current standard HTM. The hole drift mobility and the glass-transition temperatures of the tetraarylbenzodifurans were also found to be better than those of alpha-NPD.