Solid-state light-emitting electrochemical cells based on ionic iridium(III) complexes

Solid-state light-emitting electrochemical cells (LECs) have aroused great interest in recent years as novel organic light-emitting devices and a promising lighting solution. LECs have many advantages over multilayered organic lighting-emitting diodes (OLEDs), such as single layer, solution process and air-stable cathodes. In recent years, ionic iridium complexes are widely used in LECs for their high efficiencies and tunable emission colours. In this feature article, we will review the proposed operation mechanisms of LECs, the development of ionic iridium complexes and the progress in improving colour, efficiency, stability and response time of the LECs. Finally, the prospects and remaining problems will be discussed.