The Design, Synthesis And Property Research Of N-type Organic Semiconductor Based On Fluorinated Naphthalene Diimides

Recently, organic electronic have attracted considerable attention with the boom of theelectronics industry. Organic Field-Effect Transistors (OFETs) are widely applied in organicelectronics due to their advantages of easy preparation, flexibility and low-cost. Organicsemiconductors, which act as the key components of OFETs, play an important role in carriertransportation, which can influence the performance of OFETs. Therefore, the development ofOFETs should be based on the excellent organic semiconductor materials. To date, some p-type(hole transporting) organic semiconductors have shown high hole mobility, which already reachedand even exceed the level of the amorphous silicon. In contrast, the number of n-type (electrontransporting) organic semiconductors with high mobility is few. However, both the p-channel andn-channel transistors are required to construct the organic complementary logic circuits.Nowadays, naphthalene diimides (NDIs) derivatives as typical n-type organicsemiconductors have gained wide attention due to their low-lying LUMO level, high thermal andchemical stability. One of the π-expanded naphthalene diimides (NDIs) derivatives are promisingorganic semiconductor materials, due to their good stability and high electron mobility. In addition,fluorinated compounds are widely used in biology, medicine, chemical industry and photoelectricand other fields due to their unique properties. Considering fluorine atom is the mostelectronegative and relatively small atomic radius, fluorination is an effective strategy formolecular modification. This thesis focuses on the design and synthesis of a class of naphthalenediimides derivatives entailing two2-(1,3-dithiol-2-ylidene)-2-phenylacetonitrile groups, which was substituted by fluorine atom on different positions on the phenyl, and their physical/chemicalproperties and their OFET performance are investigated. It is discovered that the materials exhibitdifferent performance when the fluorine is introduced into different position of phenyl. The twocompounds performed as n-channel materials when the hydrogen in ortho-position andmeta-position was substituted by fluorine atom. Surprisingly, the compound performed as bipolarmaterial when the hydrogen in para-position was substituted by fluorine. Interestingly, when thepara-position was substituted by trifluoromethyl, the compound turns to be n-channel materialagain. What’s more, the physical/chemical properties of the compound change heavily while thefive hydrogen of phenyl were substituted by five fluorine atom. The result demonstrated that it’san effective strategy to introduce fluorine into material to modify the properties, the differentsubstituted positions of fluorine may result in great changes, which offer an novel method tomodify the molecular property.