Deep blue organic light-emitting devices enabled by bipolar phenanthro[9,10-d]imidazole derivatives

摘要: Two blue fluorescent phenanthroimidazole derivatives (PhImFD and PhImTD) with a D–π–A structure are synthesized by attaching hole-transporting dibenzofuran or dibenzothiophene an electron-transporting moiety characterized. The nonplanar twisted structures reduce molecular aggregation, which endows both of the compounds good thermal properties, film-forming abilities as well high quantum yields in CH2Cl2 solid state. Non-doped organic light emitting diodes (OLEDs) fabricated employing PhImFD PhImTD emitters exhibited promising performances. devices show deep emission Commission Internationale de l’Eclairage (CIE) coordinates (0.15, 0.11) for 0.10) PhImTD. PhImTD, desired bipolar-dominant characteristics, render low driving voltage 3.6 V. energy levels materials were found to be related donor units different substituents. Device B, using layer (EML), fitting increased electron transport ability, possesses favorable efficiencies 1.34 cd m−2 CE, 0.82 lm W−1 PE 1.63% EQE. utilized host yellow emitter, PO-01, fabricate white light-emitting (WOLEDs) that give forward-viewing maximum CE 8.12 CIE (0.339, 0.330). results demonstrated not only unit is excellent building block construct materials, but also chemical modification introduction suitable electron-donor substituent could influence performance devices.