Thieno[3,4-c]pyrrole-4,6-dione as novel building block for host materials for red PhOLEDs

In the presented work the electron accepting thieno[3,4- c ]pyrrole-4,6-dione is introduced as a novel building block for donor–acceptor based host materials for Phosphorescent Organic Light Emitting Diodes (PhOLEDs). A series of three regioisomers consisting of the thieno[3,4- c ]pyrrole-4,6-dione acceptor and carbazole donors linked via a phenylene linker was prepared and the impact of the phenylene substitution pattern on the molecular properties was analyzed. Regarding their applicability as host materials, the newly developed materials were investigated in red PhOLED devices achieving a high current efficiency of 30.6 cd A −1 corresponding to an external quantum efficiency of 17.7% and a high power efficiency of 23.8 lm W −1 . Thus, we present the first successful application of the thieno[3,4- c ]pyrrole-4,6-dione building block in host materials for PhOLEDs.