Synthesis Of π…π Stacking MOFs With The Room Temperature Phosphorescent And Optoelectronic Properties

Room temperature phosphorescence(RTP)have longer luminous lifetime and higher luminous efficiency compared to fluorescence,which have been widely used in light-emitting diodes,chemical sensing,information storage,anti-counterfeiting and other fields.Metal-Organic Frameworks(MOFs)characterize the adjustable structure and functionalization,the precise structure can be designed and synthesised to achieve the long-range orderly transition of triplet excitons and improve RTP performance.Recently,π…π interaction has been proved as an effective way to promote long-last RTP.How to design MOFs with strong π…π interaction to attain the long-lived RTP MOFs and their applications in the field of optoelectronics are the research contents of this thesis.In this thesis,some kinds of MOFs with strong π…πinteraction are designed and synthesized.The relationship between the structures、stacking mode and RTP properties was investigated,and the photoelectric response performance of RTP MOFs were further explored.The work of this thesis mainly contain the following three parts:1.[Zn3(IPOIPA)2(μ3-OH)(μ2-OH)](1)was synthesized by using 5-isopropoxym-m-phthalic acid(IPOIPA)as organic ligand.The structure analysis showed that the hexanuclear Zn(Ⅱ)can effectively immobilize the organic chromophore to enhance π…π stacking and stabilize the triplet excitons for the longlife RTP of crystal 1.The theoretical calculation results show that the effective separation of HOMO and LUMO orbitals is beneficial to the migration and separation of electron hole pairs to improve photoelectric response.Further photoelectric catalytic degradation of rhodamine B showed that the crystal 1 had good catalytic efficiency and catalytic rate.After some times of recycled degradation,which is slight reduction in catalytic efficiency,the result further confirmed the structural stability and high catalytic efficiency of crystal 1.2.[Mn0.5(NH3IPA)(H2O)](2)and[Zn(NH2IPA)(H2O)](3)were synthesized with 5-amino-m-phthalic acid(NH3IPA·H2O)chromophore as an organic ligand.Crystal structure analysis shows that crystal 2 has the strong π…π interaction,which inhibited the triplet nonradiative transition to extend the RTP lifetime.The photophysical experiment results show that crystal 2 exhibit longer RTP lifetime than crystal 3.The theoretical calculation results show that the effective separation of HOMO and LUMO orbitals in crystal 2 is conducive to the separation of electron hole pairs,and further explores the photoelectric properties of crystal 2 and crystal 3.The photoelectric experiment results show that crystal 2 has a high switching photocurrent ratio.Interestingly,crystal 3 can obtain alternating current with adjustable frequency by changing the on-off light cycle.3.[Zn3.5(TDA)4(DMF)3](Me2NH2)(4)(Me2NH2=dimethylamine cation)and[Zn(TDA)(dps)](5)were synthesized with 2,5-thiophene dicarboxylic acid(TDA)and 4,4’-dipyridine sulfur(dps)as organic ligands.The crystal structure analysis showed that the formation of Zn(II)clusters in crystal 4 can anchor more organic ligands and form strong π…π interaction,which is beneficial to improve the phosphorescent performance.Photophysical results show that the phosphorescence lifetime of crystal 4 was more than 400 times than the pure ligand.Furthermore,the photoelectric response performance of crystal 4 was tested.The results show that crystal 4 has a high switching photocurrent ratio.Crystal 5 shows abnormal photoelectric response behaviour,which possesses potential application value for data storage and anti-counterfeiting.