Synthesis And Applications Of Novel Organic Optoelectronic Functional Materials Based On Truxene

As a functional unit,truxene has been widely applied in organic optoelectronic.This thesis focuses on the synthesis and applications of novel organic optoelectronic functional materials based on truxene,which can be divided into the following three parts.One is the synthesis of three-arm star-shaped truxene small molecule nonfullerene acceptors and their application in organic solar cells;the second is the synthesis of six-arm star-shaped small molecule hole transport materials and their application in p-i-n perovskite solar cells;the third is the study of photocatalytic hydrogen evolution?PHE?by truxene conjugated porous polymers?CPPs?.In order to expand the absorption through donor-acceptor effect and improve the absorption coefficient of the materials,in Chapter 2,three small molecular acceptors centered on truene and end-capped by strong electron-withdrawing structure of 2-?3-oxo-2,3-dihydroinden-1-ylidene?malononitrile or two electron-withdrawing structure of benzothiadiazole and 3-ethylrhodanine,namely Tr?Hex?₆-3IC,Tr?Dec?₆-3IC and Tr?Hex?₆-3BR,were synthesized and applied in organic solar cells.The nearly coplanar acceptor Tr?Hex?₆-3BR based devices have achieved PCE over 2%,which was the highest efficiency for truxene acceptor at that time.However,low electron mobility,unbalanced?_h/?_e ratio,severe molecular recombination,and inappropriate phase separation scale between donor and acceptor lead to lower FF and J_sc.To enhance the?-?stacking of materials,and then increase electron mobility,in Chapter3,two small molecular acceptors of Tr-3PDI and FTr-3PDI were synthesized by using truxene as the nucleus and PDI as the arms,connected by carbon carbon single bond and benzene ring.Combined with PTB7-Th,the coplanar acceptor FTr-3PDI based devices achieved a PCE of3.8%,which was higher than that of PTB7-Th:Tr-3PDI system?2.2%?.This is due to the combination of factors,such as the increase of mobility,the increase of charge transfer,the decrease of molecular recombination,and the favorable morphology of blend film.The fused ring reaction between the core and the PDI arm plays an important role in improving the performance of organic solar cells.To enlarge the coplanar and improve the hole mobility through ring-fusion,in Chapter 4,four kinds of six-arm small molecule hole transport materials,Tr-6-1PhO,Tr-6-3PhO,FTr-6-2PhO and FTr-6-3PhO,were designed and synthesized.The above materials were used as the hole transport layer to construct p-i-n perovskite solar cells,respectively.Tr-6-3PhO,FTr-6-2PhO and FTr-6-3PhO have achieved photoelectric conversion efficiency of 17.1%,16%and16.5%in the undoped condition,respectively,which were 231%,216%,and 223%higher than that of HTL-free device?7.4%?.FTr-6-3PhO achieved the highest short circuit current of 21mA cm^-2,which is mainly attributed to the enhanced molecular planarity,the more orderly molecular stacking,the increased mobility and charge transfer.To explore the relationship between tertiary amine density and wettability,hydrogen evolution rate?HER?,in Chapter 5,a series of novel truxene-based CPPs:Tr-F8,Tr-F8-F3N-40%,Tr-F8-F3N-70%,and Tr-F3N according to the decrease of tertiary amine density,were designed and synthesized for PHE.The water contact angles of Tr-F8,Tr-F8-F3N-40%,Tr-F8-F3N-70%,and Tr-F3N decrease from 90.5°,78.2°,66.1°to 19.9°,together with the HER from⁰?mol h^-1 g^-1,102?mol h^-1 g^-1,220?mol h^-1 g^-1,to 446?mol h^-1 g^-1.With the increase of tertiary amine density,the contact angles between CPPs and water decreased,which is beneficial to the contact with water,highly improving the wettability and improving the performance of PHE.