Organic light-emitting diodes using 3- or 5-hydroxyflavone-metal complexes

3- or 5-hydroxyflavone-metal complexes were synthesized and applied to organic light-emitting diodes (OLEDs) as an emitting material and an electron transport material. When bis(5-hydroxyflavonato)beryllium [Be(5Fla)(2)] was used as an emitting material, the OLED showed a luminance of 1900 cd/m(2) with yellow, On the other hand, when used as an electron transport material in an organic three-layer cell, a high luminance of more than 10 000 cd/m(2) was obtained, Furthermore, the turn-on voltage of the OLED could be lowered to 2.4 V and its lifetime was more than 1300 h. Be(5Fla)(2) was found to have a good electron transporting capability and good stability. (C) 1997 American Institute of Physics.