Recently organic phosphors have been demanded the attention of the organic electroluminescence community because their efficiencies can be as quadruple as that of the fluorescent materials. The research was focused on the new phosphorescence dyes and host materials. The materials with high-efficient phosphorescence were relatively rare

and to date

only a few of them was found suitable for EL application such as Pt

Ir

Re

and Os complexes. The luminescence of these organometallic complexes is from metal to ligand charge transfer (MLCT) triplet state. As we know

ruthenium(Ⅱ) complex c.a. tris(bipyridyl)ruthenium (Ru(bpy)

3

2+

) was the most typical MLCT molecule polypyridine

which have been widely studied in the past half-century. The photoluminescence (PL) efficiency of those Ru complex in solution can be in the range of 7% to 50% by substituting with modified ligands. As a luminescence materials

the electrochemically generated luminescence (ECL) in a liquid cell has been extensively studied

but there are few reports on the use of these materials as emitters in a solid-state devices because Ru(bpy)

3

2+

can not be evaporated to form the film

and also can not be doped into semiconductive polymers. Considering that Ru(bpy)

3

2+

is a water-soluble molecule

the polyelectrolytes

which generally are water-soluble

may function as host of Ru(bpy)

3

to form a molecular-dispersion thin film

subsequently used for LEDs fabrication. Here we reported the properties of EL devices fabricated by doping Ru(bpy)

3

2+

into the polyelectrolytes. We have found that the type of opposite charge polymer used as host influences dramatically on the performance of the devices.