Synthesis,Structure And Photoelectric Properties Of Multifunctional Dielectric Phase Transition Materials

Multifunctional dielectric phase transition material is a new type of material with Stimuli-responsive behavior.Its optoelectronic properties are easily switched between high-intensity and low-intensity bistable states under the stimulation of external conditions,which have a broad application prospects in the fields of intelligent control,sensing and communication,photoelectric switch.The decisive nature of these optoelectronic properties and their changes are closely related to the crystal structure.The phase transition of the crystal material is often caused by the movement of molecules in the structure.Such microscop ic molecular motion is often associated with changes in the physical properties of thermodynamics,electricity and optics near the phase transition point.We try to achieve macroscopic physical properties of phase transition materials such as dielectric bistable switching,photoluminescence,electroluminescence and photoelectric switches based on micromolecular structure design.In the design of multifunctional dielectric phase change materials,we find that each component of crown ether skeleton clathrate possesses good flexibility,and structural disorder is easily occurred under the stimulation of temperature.Organic-inorganic hybrid metal halides can form zero-dimensional,one-dimensional,two-dimensional and three-dimensional different structural frame works,and small molecules of amines are easily moved or rotated in these frameworks to cause structural phase transitions.Therefore,crown ether skeleton clathrates and organic-inorganic hybrid metal halide framework compounds are very promising phase change materials.Based on the crown ether skeleton and the organic-inorganic hybrid metal halide framework,we designed and synthesized a series of phase transition materials with bistable dielectric switching properties,and discussed their structure,phase transition and their photoelectric properties in detail.(I)In Chapter Two,the crown ether(18-c-6)acted as the skeleton basis,the cyclic small molecule amine(4-amino-2,2,6,6-tetramethylpiperidine)and inorganic acid acted as an active component.A novel high temperature crown ether supermolecular phase transition material [(TAP-NH3)·(18-crown-6)·0.5(H2O)]·2(Cl O4)(1)was successfully synthesized in aqueous solution,which exhibited high temperature dielectric bistable switching properties.The low-temperature crown ether supermolecular phase transition materials 2[(TAP-NH3)·(18-crown-6)]·4(Cl O4)·2DMF(2)and 2[(TAP-NH3)·(18-crown-6)]·4(FSO3)(3)were obtained by adjusting the solvent and anion components.(II)In chapter Three,we found high-sensitivity dielectric bistable switching single-crystal material [H2dabco][Cd Cl2(SO4)](4)and normal dielectric bistable switching single-crystal material [H2dabco][Cd Br2(SO4)](5),the two one-dimensional metal halide sulfate compounds exhibited excellent dielectric "ON/OFF" performance between high and low dielectric states.On this basis,a similar structure of high-temperature phase change material [H3N(CH2)3NH3]2[Cd Cl3H(SO4)2](6)and normal dielectric materials [H3N(CH2)3NH3]2[Cd Br3H(SO4)2](7)were synthesized by modulating the cation and solvent components and using a mixed solution azeotropic method.(III)In Chapter Four,with the further development of the research,we attempted to introduce optical properties in the dielectric bistable switching by molecular design.We synthesized large-sized single-crystal and flexible thin film Im MC(Im MC =(HIm)6·[Mn Cl4·Mn Cl6])(8)with photoelectric dual "ON/OFF" properties using manganese metal halide as the structural skeleton? The material can perform synchronous "ON/OFF" switching of high and low dielectric states and different photoluminescence intensities under thermal stimulating.(IV)In C hapter Five,on the basis of the preparation of the thin film,the ferroelectric material TMCM-Mn C l3(Me3NCH2Cl Mn C l3)(9)was successfully prepared into a multi-layered(ITO/PEDO T:PSS/Nano Zn O/TMCM-Mn C l3/TPBI/Li F/Al)electroluminescent device after several times of screening and attempts.And the device exhibited stable red light over a relatively high voltage range(10-20 V).The preparation of this device laid the foundation for the subsequent research on the photoelectric coupling effects of ferroelectric ity and luminescence.