Phosphorescent emission from organic electroluminescent device

A novel organic electroluminescent device with EuGd complex (Eu_0.1Gd_0.9)(TTA)₃(TPPO)₂ as an emitter is presented, and the characteristics of the device are investigated. The phosphorescence emission from the device are observed, which are discussed in terms of yields of phosphorescence from the triplet excited state of the Gd and Eu chelates due to the strong protuberance to the spin-orbit levels of the ligands by the paramagnetic Gd³⁺ ions. Both the photoluminescent and electroluminescent efficiencies at different temperature between 77 K and 300 K are measured by integrating sphere method. Our results show that the phosphorescent emission from the triplets excited sate might be useful to improve the quantum efficiency of organic electroluminescent devices.