Design Based On Fluorene-based Hyperbranched Polymers, Preparation And Performance

In this paper,the recent progress in crosslinkable polymer and hyperbranched polymer and their application in NLO material based on fluorene have been reviewed. Some problems in this field have been found,1.The problem of stability is very important in electroluminescent polymer based on fluorene.2.How to make the crosslink procedure convenient in making the device without worse the quality of the spectrum.3.How to easily synthesis the hyperbranched polymer in order to introduce the other functional group without worsen the device quality.4.There only are a few papers about the application of hyperbranched polymer in NLO material,it's interesting to apply the synthesis hyperbranched polymer in NLO in order to reveal the relationship between function and structure.Based on these problems,the crosslinkable and hyperbranched polymers with the benzene,oxazdiazole,thiophene and Truxene as the core have been designed and synthesized.And the resulted polymers have also been applied in the electroluminescent device and NLO material.The detailed abstract of each part of this paper is listed below.1.The hyperbranched crosslinkable polymers with the benzene,oxazdiazole, thiophene and Truxene as the core have been synthesized respectively.The synthesized crosslinkable monomer has different state in room temperature with what has been reported in literature.The melting point and enthalpy was measured by DSC.The synthesized polymers were characterized and found P2,P4,P6 and P8 are well in thermostability.The resulted spectrum is well.For the polymer with lower content of the core,the spectrum is similar with what of the linear crosslinkable polyfluorene.The CV characterization showed that the energy gap increased with the increase of the content of the core.The introduction of oxadiazole is good for lowering the LUMO of the poymer.2.The intergraded sphere,luminescent microscope,AFM and device were used to characterize the synthesized hyperbranched polymer.Although the stability can be increased with the increase of the content of the core,the quantum efficiency is on the contrary.The luminescent microscope shows that:these polymers are well before annealing.After annealing in the air,the film of the linear crosslinkable polyfluorene is totally damaged,while the films of P2,P6 and P8 are still well. The AFM results show that the solubility of the initiator is different in THF and toluene.After crosslink,the RMS of these crosslinkable polymers increased.The device results show that crosslink procedure is favor to the stability of the spectrum.The electroluminescent spectrum is familiar with the one of photoluminescence.The relative lower efficiency is because of the impurity of the polymer and the simple device structure.3.The NLO effects of these polymers were tested by Mark-fringes method.The experiments results show that it is mainly from the conjugated structure.For the second EO effect,P2 and P6 show different behavior because of the different structure between benzene and thiophene.The second EO coefficient of P6 is K = 5.68122×10^-15(m / V)².4.The device and functionality of P9 with Ir complex have been explored.The content of the complex in polymer is analyzed through NMR.The thermo stability of polymer is very well.Analyzed by photoluminescence,the spectrum is very similar with polyfluorene in toluene while it is totally the emission of Ir complex in solid state.The LUMO of the polymer is very close to the work function of anode metal.With structure of ITO/PEDOT:PSS/P9/Ba/Al,the maximum brightness of the device is 169cd/m².The electroluminescence of P9 is similar with the photoluminescence one which shows the same triplet energy.