Design,Synthesis And Application Of Nitrogen-containing Heterocyclic Dynamic Resonance Organic Photoelectric Functional Materials

Organic materials,especially organic optoelectronic functional materials have been rapidlydeveloped in recent years and have become a hot spot of current research owing to their flexible molecular structure design and wide variety.Dynamic resonance structure can play an important role in tuning the photoelectric properties to design high-performance and multi-functional organic photoelectric materials with dynamic adaptability.However,the currently reported dynamic resonance materials are mostly small molecules with low quantum efficiency,and their applications are limited to the host materials of organic light emitting dioedes（OLED）devices.In address to the above issues,this thesis is introduced to heterocyclic materials modified with nitrogen atoms as building blocks to prepare high quantum efficiency aggregation-induced emission（AIE）materials,thermally activated delayed fluorescence（TADF）materials and dynamic resonance polymers.The main research contents of this paper are summarized as follows:（1）The dynamic resonance structure units N-P=X（X=O/S）were used to combine with AIE group to prepare the nitrogen heterocycle type dynamic resonance AIE materials with high quantum efficiency up to 84.29%.Therefore,the sensitive detection of explosive molecule picric acid（PA）was realized with the limit of detection（LOD）as low as 31 n M and concentration quench constant(K_SV)of 1.3×10⁵ M^-1.Meanwhile,they can be also used in write onceread many times（WORM）type storage devices showing the threshold voltage of-2.64 V and the switching ratio of 1.3×10⁴.And when used as emitters of the non-doped fluorescedt OLED devices,the external quantum efficiency（EQE）can reach up to 1.26%.（2）A new series of dynamic resonance TADF molecules were constructed by using a noveldynamic resonance structure N-C=O.The materials exhibit high quantum yields（PLQYs）up to70.04%.The TADF-OLED devices based on these emitters displayed current efficiency（CE）of 17.1cd A^-1.In addition,these molecules can be also used as the single hole transport layer of perovskite solar cells because of the compatible frontier orbital energy levels.The open circuit voltage(V_oc)about 1.05 V and the power conversion efficiency（PCE）of 20.22%were achieved,which are among the highest device performance reported so far.（3）Based on dynamic resonance monomers,novel N-C=O dynamic resonance polymers were synthesized by using the classical radical polymerization.This kind of polymers have high triplet energy and are suitable host materials for the phosphorescent OLEDs.The current efficiency（CE）of phosphorescent OLED is 5.1 cd·A^-1.