Phenanthroimidazole as molecularly engineered switch for efficient and highly long-lived light-emitting electrochemical cell

Abstract

Light-emitting electrochemical cells (LECs) based on Ir(III) complexes owing to the superior advantages exhibit high potential for display and lighting applications. Herein, a series of Ir(III) complexes based on phenanthroimidazole (PI) as an ancillary ligand were synthesized to achieve efficient and highly stable yellow-to-orange LEC devices with fast response. These complexes exhibit appropriate electrochemical stability and significant suppression of concentration quenching in the thin films compared to the archetype complex. The fabricated LECs showed remarkably long device lifetimes over 1400 and 2100 h and external quantum efficiency of 2 and 3% for yellow and orange-LECs, respectively. The obtained t1/2 for yellow LEC is much higher than archetype [Ir(ppy)2(phen)]+ and their phenanthroline-based analogues reported so far. The incorporation of an ionic tethered functional group on PI, improved the mobility of the emissive layer and reduced the device turn-on time by 75–88%. This study shows a facile functionalization and characterization of the PI ligand as well as its potential application in optoelectronic devices (OLED).

Recent advances of organic emitters in deep‐red light‐emitting electrochemical cells

“…Compared with small molecule materials, metal complexes as active materials have made much progress in the development of solid displays [18]. Since the first ruthenium complex‐based LEC was made in 1996 [42], researchers have adjusted the electronic properties of complexes by adding donor or acceptor groups [43], employing new ligands [44] or new metal cores [45] (zinc [46] and copper [47]) to build new complexes. With these efforts, metal complex materials have obtained great achievements in deep‐red LECs.…”

Characterization Studies, Photophysical and Aggregation Emission Properties of New Fluorescent 5-(4-(1H-phenanthro[9,10-d]imidazole-2-yl)phenyl)-2,4-dichlorophenyl-1,3,4-thiadiazole-2-amine

“…and analyte detection properties [9]. Among the heterocyclic compounds, phenanthroimidazole derivatives are remarkable fluorescent compounds phenanthrene and imidazole containing, which are widely used optoelectronic [10], [11], electrochemical cell [12], sensors [13], diodes [14]. Phenanthroimidazoles are excellent materials used as emission emitters in organic light-emitting diodes (OLEDs) because they have electron transport and hole-blocking properties [10], [15]- [18].…”