Solid-state electroluminescent devices based on transition metal complexes

Transition metal complexes have emerged as promising candidates for applications in solidA-state electroluminescent devices. These materials serve as multifunctional chromophores, Ainto which electrons and holes can be injected, migrate and recombine to produce light Aemission. Their device characteristics are dominated by the presence of mobile ions that Aredistribute under an applied field and assist charge injection. As a result, an Aefficiency of 10 lm\W—among the highest efficiencies reported in a single layer Aelectroluminescent device—was recently demonstrated. In this article we review the history Aof electroluminescence in transition metal complexes and discuss the issues that need to Abe addressed for these materials to succeed in display and lighting applications.