Synthesis,Characterization And Photophysical Properties Of Copper(Ⅰ) Halide Complexes Containing Thiophenyl Diphosphine And Monophosphine

Organic light emitting diodes（OLEDs）have the advantages of self illumination,high color gamut,high contrast and flexibility,and are most promising for application in future lighting and display devices.Compared with platinum（Pt）and iridium（Ir）and other precious metals commonly used in OLED,copper has the advantages of abundant reserves and low price.In particular,the luminescence efficiency of Cu（Ⅰ）complexes with thermally activated delayed fluorescence（TADF）effect is up to 100%in theory.Therefore,Cu（Ⅰ）complexes have the potential to replace precious metal materials.At present,the research shows that the luminous efficiency Cu（Ⅰ）complexes is comparable to that of some noble metal complexes.Among them,electron rich heterocyclic mononuclear Cu（Ⅰ）halide complexes with diphosphine and monophosphine have excellent luminescence properties,but are rarely reported so far.Based on the reported research on electron rich thiophene,three thiophenyl diphosphine ligands and two thiophenyl monophosphine ligands were synthesized.After reacting with Cu（Ⅰ）halide,nine new mononuclear Cu（Ⅰ）halide complexes were obtained.The structure,photophysical and thermal properties of the complexes were characterized by nuclear magnetic resonance（NMR）,high resolution mass spectrometry（HRMS）,single crystal X-ray diffraction,infrared spectrum（IR）,ultraviolet visible spectrum（UV-vis）,fluorescence spectrum（PL）and thermogravimetric analysis（TGA）.The luminescent mechanism of these Cu（Ⅰ）complexes was analyzed by density functional theory（DFT）.The thesis includes four chapters,（1）In the introduction,we introduce the luminescence principle of organic light-emitting diode materials,the research progress of various coordination forms of Cu（Ⅰ）complexes in OLED,and put forward the research content of this subject based on the existing research.（2）Ligands of L₁[（2,5-dimethylthiophen-3-yl）diphenylphosphine]and L₂[3,4-bis（diphenylphosphino）-2,5-dimethylthiophene]were synthesized.After reacting with Cu（Ⅰ）halide,three mononuclear tetracoordinated Cu（Ⅰ）halide complexes 1-3 were obtained.At room temperature,complex 1 emits greenish blue light,and complexes 2-3 emit yellowish green light.The maximum emission wavelengths are 475,526 and 531 nm,respectively.Absolute internal quantum efficiency(Φ_PL)of 1-3 in solid state at room temperature is 0.16～0.22,and they display thermally activated delayed fluorescence（TADF）,and the luminescence mainly comes from MLCT,XLCT and ILCT.（3）Ligands of L₃[diphenyl（thiophen-2-yl）phosphine]and L₄[2,3-bis（diphenylphosphino）thiophene]are coordinated with Cu（Ⅰ）halide,three mononuclear tetracoordinated Cu（Ⅰ）halide complexes 4-6 are obtained.At room temperature,complexes4-6 emit yellowish green to green light,and the maximum emission wavelengths are 519,503and 531 nm,respectively.Absolute internal quantum efficiency(Φ_PL)of 4-6 in of solid state at room temperature is 0.36～0.86.The luminescence of complex 4-6 at 298 K are mainly due to TADF,and the luminescence mainly comes from MLCT,XLCT and ILCT.（4）Using L₃and L₅[3,4-bis（diphenylphosphino）thiophene]as ligands and coordinating with Cu（Ⅰ）halide,three mononuclear tetracoordinated Cu（Ⅰ）halide complexes 7-9 are obtained.At room temperature,complexes 7-9 exhibit green to yellowish green light,and the maximum emission wavelengths are 501,519 and 531 nm,respectively.Absolute internal quantum efficiency(Φ_PL)of 7-9 in solid state at room temperature is 0.02～0.45.The luminescence of complex 7-9 at 298 K are mainly due to TADF,and the luminescence mainly comes from MLCT,XLCT and ILCT.