Studies On Dielectric Phase Transition Based On Crystals Of Methylpiperidine Derivatives

The prosperity of the information age has brought unprecedented opportunities for stimulus-responsive perovskite materials,which can be used in a variety of intelligent devices,such as signal processing,switches,lithium batteries and memory storage devices,etc.In the past few years,the physical properties of stimulation-responsive materials can be reversibly switched between different stable states by external stimuli,which has been paid more and more attention.However,the materials can't show proper properties.We need to improve the stability of perovskite materials as well as the material properties through molecular design and regulation.At present,the lack of chemical design ways is still a major challenge in the realization of new dielectric responsive materials.Fortunately,the piperidine with six-member ring show high designability,based on that,three molecular design and regulation systems were designed,fourteen new organic-inorganic hybrid perovskite materials were analyzed with their dielectric properties,crystal structure,fluorescence,second-order nonlinear optical SHG response,infrared spectrum and powder diffraction tested.The work is described from the following three parts:Firstly,with N-chloroethyl piperidine derivative quaternary amine salt as a ligand,they are[C₈NH₁₇Cl]₂[Cd Br₄](compound 1)?[C₈NH₁₇Cl][Cd Br₂(SCN)](compound 2)?[C₈NH₁₆Cl₂][BF₄](compound3)?[C₈NH₁₆Cl₂][Cl O₄](compound 4).Secondly,with 4-Chloro-1-Methylpiperidine cations as a ligand,they are[C₆H₁₂NCl]₂[Cd Br₄](compound 5)?[C₆H₁₂NCl]₂[Zn Br₄](compound6)?[C₆H₁₂NCl][Cl O₄](compound 7)?[C₆H₁₂NCl]₂[Mn Cl₄](compound 8).Thirdly,with Halomethyl piperidine derivative quaternary amine salt as a ligand,they are[C₇H₁₄NCl Br][BF₄](compound 9)?[C₇H₁₄NCl Br][Cl O₄](compound 10)?[C₇H₁₄NCl₂]₂[Cd Br₄](compound11)?[C₇H₁₄NCl₂]₂[Zn Br₄](compound 12)?[C₇H₁₄NCl₂][BF₄](compound 13)?[C₇H₁₄NCl₂][Cl O₄](compound 14).In conclusion,three molecular design and regulation approaches have been successfully adopted,which is able to improve or even trigger the dielectric properties(compound 2),photoluminescence function(compound 8)of hybrid compounds,and the compound 14 shows both the dielectric response and SHG response.