Effective blocking of the molecular aggregation of novel truxene-based emitters with spirobifluorene and electron-donating moieties for furnishing highly efficient non-doped blue-emitting OLEDs

Abstract

Several truxene-based blue fluorescent emitters bearing different functional moieties and peripheral spirobifluorene groups have been successfully designed and synthesized. Through tuning the chemical structures and electronic characters of the functional moieties, both optimized molecular configuration and elevated highest occupied molecular orbital (HOMO) energy levels have been afforded to the truxene-based emitters, representing a new effective strategy for solving the problems of molecular aggregation and poor charge carrier injection/transport associated with the truxene-based blue emitters. Owing to the sophisticated strategy, the concerned emitters can furnish highly efficient non-doped blue-emitting OLEDs with a maximum current efficiency (η_L) of 7.41 cd A⁻¹, an external quantum efficiency (η_ext) of 4.33%, and a power efficiency (η_P) of 6.79 lm W⁻¹, representing the state-of-the-art EL efficiencies ever achieved by the truxene-based blue emitters. All promising results will not only show the great potential of the concerned truxene-based blue fluorescent emitters in the field of OLEDs, but also furnish valuable clues for developing high-performance truxene-based emitters.