Design strategy of exciplex host for extended operational lifetime

Design strategy of exciplex hosts made up of a hole transport type host and an electron transport type host for extended lifetime was established by developing exciplex hosts with different energy level offsets. An examination of the lifetime of the exciplex mixed host devices clarified the design rule of the exciplex hosts for extended lifetime. It was revealed that the HOMO and LUMO level offset between the hole type host and electron type host was the lifetime determining factor in the exciplex host devices. Long lifetime was obtained in the exciplex host devices with large HOMO and LUMO level offset between the hole type host and electron type host.