Preparation Of Fluorenes-based Polymers Via Direct Arylation Approach And Opto-electrical Property

For the flexible processing, excellent thermal stability, widely emission-color tunable, higherluminance efficiency and better charge transport, fluorene-based semiconductor are served as thepotential candidate and star organic semiconductor in the organic electronics. Compared to the redor green emitter, it is a great challenge and more important to design and prepare high efficiencyand stable blue emitting fluorene-based semiconductor. However, fluorene-based semiconductorexhibited some inherent defect, such the easily oxidized into fluorenone and further result intodecreasing the stability and device performance of organic light-emitting diodes (OLEDs) forquenching the exciton (the pair of electron and hole) by fluorenone unit. Besides, the aggregation orexcimer of fluorene molecular also induced electroluminance spectra red-shifted and caused thegreen-yellow emission under electrical field. In this regard, the post-functionalization of fluorenewould be an effective method to construct the high efficiency and stable blue emitter. In this work,in consideration of the inherent drawback of poor environmental stability (oxidation) andaggregation behavior of fluorene, we rational designed and prepared a series of fluorene-basedbuilding blocks, such as spiro[fluorene-9,90-xanthene](SFX), diarylfluorene and tertiaryalcohol-con via key Baeyer-Villiger rearrangement, one pot reaction or Friedel-crafts reaction toprepare novel fluorene-based semiconductor. In contrary to the conventional method such as Suzukiand Stille reaction, we have prepared the tetrafluorobenzene (TP)-contained diarylfluorenesemiconductor via unique direct arylation reaction. As a result, we have constructed novelfluorene-based trimer, tetrafluorobenzene, SFX-TP-SFX, and fabricated efficiency deep-blueemitting OLEDs (CIE:0.15,0.08). And compared to the homopolyfluorenes (PODPF, PCzODPF,PPFOH), the emission spectra of copolyfluorenes (PODPF-TP, PCzODPF-TP, PPFOH-TP)exhibited blue-shift, that showed deep-blue emission. And the introduction of TP unit woulddecrease the LUMO and HOMO energy level.