Addition of a Phosphorescent Dopant in Electroluminescent Devices from Ionic Transition Metal Complexes

Ionic transition metal complexes have emerged as promising candidates for applications in solid-state electroluminescent devices. This is due to the fact that a single, solution-processable layer sandwiched between two air-stable electrodes can yield high-efficiency devices. In this paper we demonstrate tuning of the emission of these devices in the red part of the spectrum by dispersing an ionic osmium complex into an ionic ruthenium complex matrix. This is shown to lead to devices that are more efficient than those from pristine films of the matrix or the dopant alone. These devices also show improved stability compared to devices based on the matrix and feature an emission spectrum that can be tuned by the concentration of the dopant.