A novel europium chelate, Eu_2(DBM)_4(Sq) Phen_2, which has a bridge ligand of squaric acid, was synthesized and used as organic electroluminescent materials. Five light-emitting diodes using TPD as hole-transporting material, Eu_2(DBM)_4(Sq)Phen_2 as emitting material, and A1Q as electron-transporting material were fabricated. The results indicate that this europium chelate possesses both hole-transporting and electron-transporting abilities. When the structure of device is UO/TPD, 50 nm/Eu_2(DBM)_4(Sq)Phen2, 20 nm/AlQ, 50 nm/LiF, 1 nm/Al, 200 run, the maximum luminance of 91 cd/m~2 at 16 V was achieved.

Key words: SQUARIC ACID, EUROPIUM COMPLEX, ELECTROLUMINESCENCE, LUMINESCENT MATERIALS, HYDROXY QUINOLINES, ALUMINIUM, ELECTRON TRANSFER