| Organic light-emitting materials represent a promising branch of organic optoelectronic materials, which are widely used in organic light-emitting diodes (OLEDs), organic sensors, etc. Comparing with traditional inorganic photovoltaic materials, Organic optoelectronic materials have shown great advantages over inorganic materials in weight, cost and technique for preparing large area flexible device, which makes organic optoelectronic materials an attracting area in recent years.In the various applications of organic optoelectronic materials in photoelectric devices, the organic optoelectronic materials are in the form of thin solid film or solid state. Although a lot of organic luminescent materials show strong fluorescence with high quantum yields in solution, their fluorescence quantum yields would drop dramatically or even quenched completely in the solid state, because of the intermolecular interactions. Therefore, it’s still a challenge to design and prepare organic light-emitting materials of high fluorescence quantum yields in solid state.Perylene tetracarboxylic acid diimide (PDI) derivatives are a group of important organic dyes because of their various applications, such as liquid crystal, organic field-effect transistors (OFET), organic light emitting diodes (OLED) and solar cells. PDIs are well known for their excellent photochemical and thermal stabilities and high fluorescence quantum yields. But the varied applications of PDI in different fields require different photophysical or chemical properties, which can be achieved by introducing different substituents at different positions of PDI molecules. Optimizing the performance of organic materials by introduction of inorganic groups has been a hot topic and achieved great progress. In this paper, inorganic groups have been introduced to organic semiconductor PDI molecules, and a series of new PDI derivatives are prepared. Their photophysical properties are studied and the relationship between structure and properties are explored, which provides references for the design of high fluorescence quantum yields of organic optoelectronic materials and fine organic semiconductor material. This thesis is composed of three parts:Chapter 1:The sythetic methods and basic properties of PDI derivatives have been reviewed. The research progress of high fluorescence quantum yields PDI derivatives are discussed. A brief overview of the properties and prospects of POSS containing organic-inorganic hybrid materials are also include.Chapter 2:POSS groups were introduced to the imide N,N’positions of PDI, and their photo physical properties in solution were investigated by UV-vis absorption spectroscopy, fluorescence spectroscopy and fluorescence quantum yield measurement. The results indicate that the POSS groups do not show large effects on the spectroscopic properties of PDIs in solution. However, the solid state spectroscopic properties of these compounds are significantly affected by the bulky POSS groups. The presence of bulky POSS groups changes the packing structure of the molecules in the solid state, some of them can be seen from the crystal, and thus affects the solid state emission properties. Our results revealed that the introduction of bulky POSS groups into the molecules will not inevitably lead to promoted solid state fluorescence quantum yield as expected. It is the packing structure of the molecules in the solid state which determines the solid state fluorescence quantum yield. If the presence of bulky POSS groups leads to the formation of "J" aggregates in the solid state, then the solid state fluorescence quantum yields will be improved significantly. Otherwise, if the bulky POSS groups cause"H"type aggregation of the molecules, the solid state fluorescence quantum yields will be small.Chapter 3:We describe the synthesis method of a novel fluorene-PDI compound, the optimal molecular structure of ground-state has been calculated for the future properties investigation. |
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