Design,Synthesis And Electroluminescent Properties Of Phenanthroimidazole-based AIE Molecules

In the era with the rapid development of organic luminogens,Organic light-emitting diodes?OLEDs?have a huge applications prospect in flat-panel displays technology and solid-state lighting resources.In order to achieve remarkable full-color display,the blue,green and red?most basic colors?are equally important to be developrd.However,in comparison with the other two primary-color emitters possessing relatively satisfied performance,the blue luminogens do not demonstrate the required efficiencies,due to their inherent wide-band-gap and the problem of stability.Furthermore,most of organic luminogens usually suffer badly from aggregation-caused quenching?ACQ?effect in the solid state,partially limiting the device performance.Various physical and chemical approaches have been attempted to alleviate the ACQ effect.A molecular with aggregation induced emission?AIE?effect was reported in 2001,which made the efficient increased even just for the solid-state.In the past few years,a large number of blue and deep blue materials with AIE effect have been reported,but which has a good efficiency and high stability is still scarce.Recently,for design of the blue fluorescent materials,the phenanthroimidazole–based derivatives as the building blocks provide researchers much more inspiration.Because of its relatively stable transmission and injection ability,excellent luminous efficiency and stability,these is a in huge space for the deep blue/blue AIEgens exploring in the field of fluorescent material.The research of this thesis is focusing on the design and synthesis of the series of deep-blue and blue AIE materials with the PPI part in non-doped OLEDs.The main contents and results are as follows:In chapter 1:The phenomenon and machanism of AIE moleculars,the historic development and current situation were outlined.Then,the moleculars which contain the phenanthroimidazole were mainly reviewed.And finally,the synthetic ideas of the thesis were put forward.In chapter 2:Four phenanthroimidazole based fluorophors with TPP moiety peripheries?3,4-BTPP-PI,4,4-BTPP-PI,3,4-BTPP-PPI and 4,4-BTPP-PPI?were designed and synthesized.The introduction of bulky TPP unit to the same bulky phenanthroimidazole will make a bigger twisted angle and crowder intramolecular space,it partially control the intramolecular conjugation.As for 4,4-BTPP-PPI,further control of the conjugation was achieved,including linkage position and the situation of the?-conjiagation.These four luminophors exhibit blue emissions from 405 nm to 412 nm with the L_max and?_Cmax up to6723 cd m^-2and 2.0 cd A^-1.And the CIE coordinate at?0.15,0.07?.In chapter 3:Three phenanthroimidazole based fluorophors with tPE moiety peripheries?3,4-BtPE-PI,4,4-BtPE-PI and 3,4-BtPE-PPI?were designed and synthesized.The introduction of tPE unit which both more flexible and bigger will control the intramolecular conjugation by change the linkage mode and the situation of the?-conjiagation.By using these simple ways to effectively improve the current efficiency of the target devices and controlled the intramolecular conjugation.Finally,the AIEgens exhibit deep blue emissions?430 nm?with the L_max and?_Cmax up to 22.196 cd m^-2 and 3.8 cd A^-1.In chapter 4:Four phenanthroimidazole based fluorophors with TPA/CZS moiety peripheries?4,4-BTPA-PI,4,4-BCZS-PI,4,4-BTPA-PPI and 4,4-BCZS-PPI?were designed and synthesized.The introduction of containing heteroatoms units make the whole intramolecular conjugation much smaller.TPA/CZS unites are introducted in to increase the charge injection and transport properties.According to change the linkage mode and control the intramolecular conjugation controlling the conjugation of TPA/CZS groups to make the molecular more twisted.These four luminophors in this part all showed well charge injection and transport performance for whole moleculars.For the further developing of the new doped OLEDs including preparation and implementation of full color lighting provides a new design or reference accordingly.