Synthesis And Luminescent Properties Of Small Molecules Based On Carbazole Derivatives

Organic small molecule luminescent materials are widely used as optoelectronic function materials,security and anti-counterfeiting,due to their wide variety,comprehensive color,high color purity and flexible molecular design.Carbazole is an excellent luminescent molecule,its molecular structure could be modified by adding other functional groups to improve the luminescent properties of carbazole-based materials.In this work,carbazole derivatives with spatially located isomeric features were synthesized,secondly,D-A-A type compounds were synthesized by introducing different electron-absorbing groups into the carbazole ring;in addition,four blue-light materials were prepared by introducing carbazole groups on anthracene(bianthracene)nuclei.Their luminescent properties were investigated by spectral analysis,lifetime decay curves,crystal structure and stacking,electrochemical and theoretical calculations.In the chapter 2,Two positional isomorphisms,DBC and DPZ,were prepared by introducing carbazole groups at the 2,4 and 2,4' positions of benzophenone.In the solid state,the phosphorescence lifetime of DBC is longer,due to the tight molecular stacking,DPZ has a significent pressure-induced discoloration due to the loose molecular stacking.With increasing solvent polarity,the redshift of the absorption spectrum of DBC(DPZ)is smaller,while the redshift of the luminescence spectrum is obvious.In the chapter 3,a series of D-A-A type compounds 2PC,3PC,4PC,BDPC and CNPC were synthesized by introducing the double absorbing electron group pyridine etc.In addition to the D-A type carbazole-pyridine compound PC as a reference.The effect of different electron-absorbing groups on the luminescence performance of compounds was investigated.With increasing solvent polarity,the emission peaks of 2PC,3PC,4PC,BDPC and CNPC were significantly red-shifted,which indicated that the D-A-A type compounds were more favorable for charge transfer.In the solid state,the emission peaks of 2PC,3PC,4PC and CNPC were significantly redshifted.In Chapter 4,Four carbazole derivatives with high spatial site resistance,PCA,DPCA,PCBA and DCBA,were prepared by introducing a carbazole group on the anthracene and bianthracene nuclei,respectively.All four compound solids emitted blue light and the CIE coordinates indicated that the color purity of PCA was higher.With increasing solvent polarity,the redshifts of the absorption spectra of the four compounds were smaller,while the redshifts of the luminescence spectra were obvious,among which,the redshifts of PCA and DCBA were larger.