Efficient doped red light-emitting electrochemical cells based on cationic iridium complexes

We demonstrate an efficient red emitting host-guest LEC based on cationic iridium complexes. The host-guest LEC has brightness of 8.4 cd m−2, external quantum efficiency (EQE) of up to 3.5% and peak current efficiency of 3.4 cd A−1, the highest efficiencies reported to date for red-emitting host-guest LECs based on cationic iridium complexes. It is confirmed that dispersing the guest molecules into the host matrix would greatly inhibit the self-quenching of the guest molecules in the emissive layer and thus improving the device efficiency, and offering an effective approach to improve device efficiencies of LECs.

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► An efficient host-guest red emitting LEC is realized with cationic iridium complexes.
► High external quantum efficiency (EQE) of up to 3.5% and current efficiency of 3.4 cd A−1 are achieved.
► It is confirmed that doping could depress self-quenching in the emissive layer and improve device efficiencies.