Synthesis And One-Dimensional Self-assembly Properties Of Series Of Electron Transport Materials

Owing to their specific advantages and features, organic semiconductors which are mainly divided as electron transport materials and Hole transport materials are widely used in various fields such as Organic light emitting devices (OLEDs), Organic solar cells and Organic field effect transistors in recent years. The electron transport materials are much fewer than the hole transport materials due to their sensitivity and vulnerability to the air and moisture, which become the main challenge to the development and application of organic devices. As a result, tremendous research effort has been made to design and synthesize readily processible and robust electron transport materials in decades.The nano-science is an interdisciplinary integrated system of materials science, life science, information science and many other sciences. During the investigation of the materials, many results have revealed that the characteristics of the materials are not only depending on their chemical structures but also their molecular aggregations. The functions of the aggregations are mainly reflected in their influence to the structures and the properties of the materials. However, comparing with the single-molecule and macro-size state, it is still in fancy for people to comprehend the structures and the properties of the materials in mesoscopic state (nano-/ micro-/ mesoscales) and the relationship between them. The organic nanocrystals and their performance reported by now demonstrate the fascinating charm and enormous development potential of this research field. Being an essential component of the organic micro-structure, organic one-dimensional nanomaterials have been widely concerned owing to their specific nature and the applications prospects in organic micro-electronic device.It is the prerequisite for developing new materials to explore the potential of the organic electron transport materials, get the photoelectric material system with excellent performance and understand the relationship between the semiconductors'structures and properties. In addition, In addition, using the molecular interactions to investigate the organic self-assembly will be meaningful to expansion of the materials'application scope. Considering all the aspects above, our studies mainly focus on the three aspects:1. Hoping to get the stable materials with excellent transport performance by adjusting the molecular structure, we report the design and synthesis of series of electron transport materials. The NMR, mass spectroscopy and element analysis were used to characterize the structures of these compounds. We also used the cyclic voltammetry method to calculate the energy level of these compounds, and the results we got were compared with those of classic electron transport materials. With the help of these results, we could further define the status of these compounds as good electron transport materials. 2. We tried to cultivate the single crystals by using the compounds we synthesized and successfully obtained four of them. Basing on the analysis of these single crystals, we got such conclusion: There is no hydrogen bond orπ-πinteraction in the crystals of TCNQ and F4TCNQ. The three peripheral rings are not at the same plane with the central benzene ring. The molecules do not have anyπ-πinteraction, however they have strong intermolecular hydrogen bond. The TPBI and methanol form the supramolecular crystal with the ratio of 1:1. There are two different confirmations (planar and twisting) in the crystal of TCTDT and the ratio is 2:1. Further isolation and analysis of these confirmations will provide us opportunity to know about the relationship of their structures and properties. Although TCTDT don't have any hydrogen bond, there is strongπ-πinteraction in it, which is the key element of good charge transport materials. As for TCNQ/F4TCNQ and TPBI which don't haveπ-πinteraction, they serve as good electron transport materials mainly because they could keep themselves stable after accepting electrons.3. Considering the goodπ-πinteractions in the TCTDT/TCSDT molecules, we studied their characters of self-assembly. We got different 1-Dimensional self-assembly structures with different methods and conditions: we got the organic nano-tubes of TCTDT in acetone and DMF while the nano-tubes of TCSDT were obtained in acetone only. Both of structures were gained by using the method of solvent evaporation. We also got the ultra-long micro-linear structures after introducing the alcohol with different alkyl. We characterized the structures and the results revealed that the self-assembly structures had the transitional state between the dilute solution and the single crystal. The results not only elucidated the relevance between the materials'structures and properties, but also provided theoretical basis for us to control the optical and electrical properties by adjusting their self-assembly structures.In conclusion, we synthesized series of electron transport materials and obtained single crystals of four compounds. We prepared two specific self-assembly structures with TCTDT/TCSDT and studied their properties. All these results elucidated the relationships between molecular structures/molecular packing structures and physical chemistry properties of materials.