Solid-state white light-emitting electrochemical cells using iridium-based cationic transition metal complexes

White electroluminescent (EL) emission from single-layered solid-state light-emitting electrochemical cells (LECs) based on host-guest cationic iridium complexes has been successfully demonstrated. The devices show white EL spectra (Commission Internationale de l'Eclairage coordinates ranging from (x, y) = (0.45, 0.40) to (0.35, 0.39) at 2.9-3.3 V with high color rendering indices up to 80. Peak external quantum efficiency and peak power efficiency of the white LEC reach 4% and 7.8 Im/W, respectively. These results suggest that white LECs based on host-guest cationic transition metal complexes may be a promising alternative for solid-state lighting technologies.