Research On The Excited State Properties Of Organic Conjugated Macromolecule

The new energy material research and development always is one focus which the people pays attention. The compound excited state property are more limited by the computer condition and the choosing methods, so seeking the appropriate method to computate the excited state of organic compound is very valuable. Excited state properties of novel p- and n-type organic semiconductors and 1,1-Disubstituted 2,3,4,5-Tetraphenylsiloles with a thiazolothiazole unit are theoretically investigated with quantum chemistry methods and time dependent the density functional theory method. Firstly, the optimized geometries of them are investigated, then studing the excite state of the organic compound according to the energies and densities of frontier orbital HOMOs and LUMOs. Studing the photoelectric conversion of organic compound as well as the property. The molecule structure and charge transfer and other information learn from the excited state molecule.Great significance to great significance to new photoelectric materials in the design and exploitation .This has established the foundation for the exploration the relations of energy material structure and property, and has provided the valuable theory basis for the experimental study.1.The structures and excited state properties of novel p- and n-type organic semiconductors with a thiazolothiazole unit are studied with electronic structure theory and the methods of the transition density matrix, transition and charge difference densities. The calculated vertical absorption frequencies of them are consistent with the experimental data. The dihedral angles between the thiazolothiazole unit and the trifluoromethylphenyl (or thiophene) in the vertical absorption processes are examined from the geometries of optimized ground states. To study the influence of the individual units of the derivatives to the excited state properties of the derivatives.The energies and densities of frontier orbital HOMOs and LUMOs of the individual unit and the derivatives reveal there is a stronger localization for the derivative 1 than that for the derivative 2. The electron-hole coherence and excitation delocalization shows the photoinduced dynamics information: there is a better excitation delocalization for the derivative 2 than that for the derivative 1.2.The excited state properties of 1,1-Disubstituted 2,3,4,5-Tetraphenylsiloles were investigated theoretically with quantum chemistry method as well as the transition and charge difference densities. Study the Crystal structures, thermogravimetric properties, PL, charge carrier transport characteristics and Transition density of 2,3,4,5 -tetraphenylsilole derivatives having different substituents at the 1,1-positions. experimental results suggest that high charge carrier mobilities and high PL efficiencies are the main origin of the excellent EL performances of MPPS and HPS. The theoretical results reveal that the orientation and strength of dipole moment for neutral and charged species are significant different from the studying of the transition densities for neutral and charged species; and the orientation and result of the charge transfer are also different. The theoretical results also reveal the contribution of the substituents at the 1,1-position to the excited state properties of 2,3,4,5-Tetraphenylsiloles.