Carbazole-functionalized V-shaped bis-coumarin derivatives as organic luminescent materials

Two novel functionalized V-shaped bis-coumarin derivatives, namely CC-Cz and CC-2Cz, were successfully synthesized and characterized. The thermal stability, photophysical and electrochemical properties of the compounds were investigated systematically. By combining theoretical and experimental investigation, to reveal the structure-property relationships of different substituted coumarin-fused coumarins. These compounds possess good thermal stability with decomposition temperature over 360 °C, and exhibit strong green emission in solution and solid thin films. The solution-processed doped devices using the blend of PVK:PBD with the V-shaped bis-coumarin derivatives as emitting layers emit green emission with maximum external quantum efficiency (EQEmax) of 2.20% for CC-2Cz, 1.98% for CC-Cz.