Design,Synthesis And Properties Of Intrinsically Stretchable PDI-based N-type Interface Materials

The properties of interface materials have an important impact on the performance and stability of organic optoelectronic devices,which has been widely concerned in recent years.According to the types of carriers,the interface materials can be divided into p-type and n-type.The design and synthesis of p-type organic interface materials are relatively mature,while the development of n-type organic interface materials（electron transport materials）is relatively backward.Perylene diimide（PDI）and its derivatives have become one of the most widely studied electron transport materials due to their electron deficient,electrochemical and photophysi cal properties,and have attracted much attention in the field of organic optoelectronic materials.It is one of the important methods to obtain high-performance electron transport materials by reasonably changing the modification groups of molecules to co ntrol the photoelectric properties of materials.The key to directly affect the photoelectric properties of materials is to change the structure of molecular materials and the interaction between molecules.In this thesis,a series of perylene diimide based n-type interface materials with large conjugated plane and strong electron acceptor were designed and synthesized.N-type small molecule interface materials were designed and synthesized by introducing polar groups containing hydrogen bonds into bay site of perylene diimide.The effects of hydrogen bonds on electron transport and device performance were systematically studied.However,this kind of rigid perylene diimide n-type small molecule interface material itself does not have tensile properties,which limits its application in the field of stretchable electronics.Therefore,a series of intrinsic stretchable n-type organic interface materials are designed and synthesized,which solved the problem of non stretchability of traditional interface materials and improved the stretchability of op toelectronic devices.This thesis provides guidance for the design and synthesis of high-efficiency intrinsic stretchable electron transport materials.（1）Design,synthesis and performance research of PDI based n-type small molecule interface materials.Perylene diimide is an electron deficient molecule with large conjugated plane.Many studies have reported its outstanding electron transport properties in organic solar cells.PDI-2BIA,an n-type small molecule inter face material based on perylene diimide,was designed and synthesized by introducing hydrogen bond containing modification groups into the bay of perylene diimide.The material was applied to the n-type interface layer of organic solar cells,and compared with the widely used PDINO electron transport material without hydrogen bond,Their electrochemical and optical properties were studied.The results show that compared with PDINO without hydrogen bond,the absorption peak of PDI-2BIA is red shifted because of hydrogen bond,and the intermolecular interaction is enhanced by hydrogen bond,which improves the electron transport performance.The photoelectric conversion efficiency of organic solar cells is the highest,reaching 17.18%.This kind of hydrogen bo nd interaction has important reference value for the design and development of new electron transport materials.（2）Design,synthesis and performance research of PDMS-PDI intrinsic stretchable n-type interface material.The electron deficient perylene diimide unit was introduced into the high tensile elastomer PDMS（amino terminated polymethylsiloxane）by chemical crosslinking,and MPU（4,4’-methylenebis（phenylurea））with strong hydrogen bond was introduced into the main chain as buffer.A series of high tensile,high tensile and low molecular weight polymers were prepared by using rigid flexible control strategy a nd simple polymerization method.The efficient and stable electron transport elastomer solves the inherent inextensibility problem of traditional organic optoelectronic materials.The maximum tensile strength of PDMS-MPU_0.8-PDI_0.2 is 940%.When PDMS-MPU_0.8-PDI_0.2 is used as an n-type interface material in organic solar cells,the highest photoelectric conversion efficiency is 8.24%.In this study,a series of intrinsic stretchable n-type interface materials were designed and synthesized for the first time,and their applications in organic solar cell devices were realized,which provided a new design idea for the preparation of high-performance stretchable photovoltaic devices.（3）Design,synthesis and performance research of PEI-PDI intrinsically stretchable n-type interface material.The preparation of the intrinsic tensile n-type interface material was realized by introducing the perylene diimide unit into the high tensile elastomer by means of rigid and flexible control strategy,but its tensile and electronic transmission properties were still limited.In order to further improve the tensile properties and electron transport properties of the materials.Perylene diimide,an organic electron transport unit is introduced into PEI（polyethyleneimine）with multiple crosslinked network structure by chemical crosslinking.A series of high elastic and low molecular weight films were prepared by adjusting the ratio of rigid and flexible segments,polymer size and film morphology.The efficient and stable electron transport elastomer solves the inherent inextensibility problem of traditional organic optoelectronic materials.