Triphenylethene-carbazole-based molecules for the realization of blue and white aggregation-induced emission OLEDs with high luminance

Molecules that use triphenylethene-carbazole moieties decorated with different substitutions were designed and synthesized, harvesting wide energy bandgaps and aggregation-induced emission (AIE) characteristics. The photophysical, thermal, and electroluminescence (EL) characteristics of the designed emitters were investigated to clarify the molecular structure-property-performance relationship. The photoluminescence spectra of the synthesized molecules measured using tetrahydrofuran-water solution presented strong blue emissions, confirming their AIE property. The doped blue-emitting organic light-emitting diodes (OLEDs) with compound 2 exhibited satisfactory peak efficiency of 8.7 cd/A and high maximum luminance of 18474 cd/m2. In comparison, the peak efficiency of the 2-based sky-blue OLEDs with a non-doped emitting layer was 10.2 cd/A with an even superior peak luminance of 39661 cd/m2. Blue-emitting AIE OLEDs have rarely presented such high luminance values, and this improvement can facilitate the development of white-emitting OLEDs (WOLEDs) for lighting applications. The fabricated WOLEDs with 2 achieved a maximum efficiency of 5.6% (8.0 cd/A and 7.5 lm/W), stable EL spectra, and high luminance of 29319 cd/m2. These results indicate that the triphenylethene-carbazole structure designs for AIE molecules could simultaneously harvest wide energy bandgap and high luminance, demonstrating their high potential for EL applications.

Automated summary

Molecules with wide energy bandgaps and aggregation-induced emission characteristics have been designed and synthesized. The results show that these molecules exhibit high efficiency and high luminance, making them promising for applications in organic light-emitting diodes.