Recently, the fields of organic light-emitting diodes (OLEDs) and light-emitting electrochemical cells (LECs) have improved tremendously with regard to tunable emission, efficiency, brightness, and thermal stability. Imidazole derivatives are excellent deep blue-green light-emitting layers in the OLED or LEC devices. This Review summarizes the major breakthroughs of various electroluminescence (EL) layers with imidazole-containing organic or organometallic derivatives, the molecular design principles, and their light-emitting performances as effective EL materials. The highly tunable chemical structures and flexible molecular design strategies of imidazole-based compounds are advantages that provide great opportunities for researchers. They can provide a good basis for the design and development of new EL materials with narrower emission and higher efficiency. Moreover, imidazole compounds have demonstrated breakthrough performances in thermally activated delayed fluorescence (TADF) properties where triplet excitons are utilized to inhibit anti-intersystem quenching, showing great promise in breaking the theoretical external quantum efficiencies (EQE) limits in traditional fluorescent devices.
Keywords: electroluminescence (EL); emitters; imidazole derivatives; light-emitting electrochemical cells (LECs); organic light-emitting diodes (OLEDs).
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