Enhanced Brightness of Eu³⁺ Complex in Organic Electroluminescent Devices by Using Another Rare-Earth Ion

Rare-earth ions Tb³⁺ ion and La³⁺ ion were used as a bridge to improve the energy transfer from the polymer to an Eu complex. The material Tb(La _0.5Eu_0.5(BSA)₃phen was synthesized and used as the emission layer in the device: ITO/PVK:Tb(La)_0.5Eu_0.5(BSA)₃phen/Alq/Al. The two device were compared in details and it was found that the device used La_0.5Eu_0.5(BSA)₃phen as the emission material had better Monochromatic characteristics with the maximal brightness of 102 cd/m² and the colour coordinates x = 0.55 and y = 0.36.