Synthesis and properties of novel spirobifluorene-cored dendrimers

Two novel spirobifluorene-cored dendrimers containing polyphenylene dendrons with the carbazole (spiro-Cz) and cyano surface groups (spiro-CN) were synthesized and characterized. Both the dendrimers show good solubility in common organic solvents. Spiro-Cz is amorphous even when it is obtained directly from organic solvents and an extremely high glass transition temperature of 332 °C is detected. These dendrimers can be reversibly oxidized and reduced in electrochemical measurements. They are blue fluorescent with small red-shift in solid film absorption and fluorescence spectra. These advantageous merits are suggested to benefit from the combined contribution from the spirobifluorene core and the bulky polyphenylene dendrons. They were used as emitting layer to fabricate organic light-emitting diodes (OLEDs). Deep-blue electroluminescence was obtained for both dendrimers devices.

► We report synthesis and properties of new spirobifluorene-cored dendrimers. ► These dendrimers are amorphous with extremely high glass transition temperature of 332 °C. ► These dendrimers are blue fluorescent with small red-shift in fluorescence spectra of solid films. ► These dendrimers can be reversibly oxidized and reduced. ► These dendrimers exhibit deep-blue electroluminescence in organic light-emitting diodes.