Monodisperse star-shaped compound and its blend in uncapped polyfluorene matrices as the active materials for high-performance pure blue light-emitting devices

The authors have demonstrated high-performance blue light-emitting device based on a monodisperse star-shaped compound. The single-layer device fabricated with solution procedure exhibited a turn-on voltage of 3.5 V, maximum luminance of 5545 cd m-2, luminance efficiency (LE) of 1.09 cd A-1, and external quantum efficiency (QEext) of 1.51% with the CIE coordinate of (0.16, 0.12). The authors also blended this highly efficient monodisperse compound in uncapped polyfluorene matrices. Enhanced performances of the uncapped polyfluorenes were obtained with improved electroluminescent stability. A maximum LE of 2.33 cd A-1 and QEext of 2.95% were achieved.