Donor-acceptor 9-uncapped fluorenes and fluorenones as stable blue light emitters

The "green emission defect" (GED) produced by fluorenones has significantly retarded the commercial scope of fluorene-based B-OLEDs. In this paper, for the first time, it is demonstrated that the "green light" emitting fluorenones 7 can be converted to "blue light" emitting fluorenones 10 by appropriate positioning of donor-acceptor and chromophoric groups onto the fluorene/fluorenone backbone. Additionally, we report an elegant highly rapid synthetic route for donor-acceptor fluorenes and fluorenones at room temperature with excellent yields.