Novel thieno-[3,4-b]-pyrazine derivatives for non-doped red organic light-emitting diodes

Two novel red fluorescent thieno-[3,4-b]-pyrazine-cored molecules containing tetraphenylethylene as peripheral groups, T-TP and T-TP1, are designed and synthesized. Their photophysical, electrochemical and electroluminescent properties are investigated. They are characterized by large Stokes shifts of over 100 nm. The bulky peripheral groups enable these molecules to be well soluble and provide the site-isolation effect on the planar emissive core. These novel materials are used as non-doped emitting layer to fabricate organic light-emitting diodes (OLEDs) by vacuum evaporation technique. Saturated red emission is obtained with a maximum brightness of 1385 cd m(-2) and a luminance efficiency of 0.66 cd A(-1). (C) 2012 Elsevier Ltd. All rights reserved.