Synthesis And Properties Of C₃-symmetric N-type Organic Semiconductor Materials

In recent years,with the rapid development of organic devices,the design and synthesis of organic semiconductor materials with high optical and electrical properties,has become the most important direction for the new generation of photoelectric device,and has the great practical guidance for the device's industrialization at the same time.In the last few years,more and more scientists are committed to design and synthesize of high-performance n-type or p-type organic semiconductor materials,for example,the way to synthesize n-type materials with high performance and air-stable.Compared to the p-type materials,the development of n-type materials is less,and their device performance is not very high.Part of the reason is that most n-type materials have poor staibility in the air,and if you leave the n-type materials under the air for a period of time,they will be deteriorated.So design and synthesis of high performance and high air stability of n-type materials has become a major challenge for organic semiconductor device.In all reports for the n-type materials,the rylene diimides account a large part.It mainly because the imide structure has strong electron withdrawing propertity,which can meet the requirements for the n-type materials.It is this character that could widely studied in organic field-effect transistors and organic solar cells.So the topic goal of this article is:on the basis of aromatic imide system,choosing the high selectivity chemical coupling reaction,synthesizing new type of organic conjugated molecules efficiently,and extending the new molecular system,preparing the target materials with high performance and high stability,and further research on its application in organic devices.The main contents are as follows.Firstly,using naphthalene ring containing imide as the basic framework,a C₃ symmetric propeller polycyclic aromatic hydrocarbon was synthesized through simple and efficient the Yamomoto coupling reaction catalyzed by Ni.The compound contains three imide groups with their angle of 120°.Their photoelectric properties are tested.The absorption and electrochemical properties showed that the molecule is a typical n-type material.The theoretical calculation shows that the molecular structure almost like a plane.DTI acceptorsbased solar cell shows power conversion efficiency of 0.69%,the OFET exhibited field effect mobility of2.6×10^-4 cm² V^-1 s^-1,an on/off ratio of 10⁵.Secondly,through the Suzuki coupling reaction and Lewis acid catalyzed cyclization reaction,synthesized a five membered ring containing perylene diimide derivatives,and further by the ring forming reaction synthesized an imide compounds.After test and characterization,it is found that the expansion of the conjugated system makes the ultraviolet absorption of the molecule obvious red shift and the band gap of the energy level decrease.The theoretical calculation has been carried out and the results of the theoretical calculation are in agreement with the results obtained by the electrochemical test.PTI acceptorsbased solar cell shows power conversion efficiency of 0.49%.