Design,Synthesis And Application Of Fused Ring Small Molecule Materials And Imide Polymer Materials

Two-dimensional conjugated fused-ring small molecular materials based on benzodithiophene(BDT)core have many advantages,such as good solubility,film-forming ability,wide absorption spectra range,easy modification of structures,etc.which have become a hotspot research field in recent years.In addition,imide polymers also have received widespread attention in recent years due to their high carrier mobility,large rigid planarity,and easy modification properties.Therefore,a series of fused-ring small molecule acceptors,perylene diimide(PDI),and naphthalene diimide(NDI)polymers were designed and synthesized in this work,we studied their physical and chemical properties,and their applications in organic solar cells.1.We design and synthesis the fused-ring small molecular acceptors based on benzodithiophene(BDT)core and application in the organic photovoltaics.In this work-thienyl-substituted(BDT)as building blocks,and thiophene ring as end fusing-ring groups based on dicyano-substituted indiones(INCN),we successfully synthesized small molecule acceptor BDTCH-IC.Meanwhile,another small molecule acceptor BDTSF-IC was obtained with alkylthienyl and fluorine substituents by optimizing thienyl conjugated side chains.The absorption edges of BDTCH-IC and BDTSF-IC are red-shifted to 824 and 793 nm,the electron mobilities are 1.271 × 10-4 cm2 V-1 s-1 and 1.519 × 10-4 cm2 V-1 s-1,respectively.Using polymer donor PM6,the power conversion efficiency(PCE)of organic solar cells is up to 13.10%based on PM6:BDTSF-IC.2.We design and synthesis perylene diimide polymers and their photovoltaic application.PDIs units possess high molar extinction coefficient,multiple chemical modification positions.However,due to the large rigid molecular planarity,resulting in the excessive molecular aggregation and poor solubility.Therefore,introducing C11 alkyl side chains improves the molecular solubility,and then electron-rich units bithiophene was introduced at the 1,7 bay position of PDI to expand the conjugate system,three polymers AP001,AP002,AP003 are obtained by using PDI and(BDT)units with different side chains polymerization.All three polymers have a wide absorption spectra(300-800 nm)and high thermal stability(Td>350℃).Because the introduction of fluorine atom slightly down-shift the lowest unoccupied molecular orbital(LUMO)energy level of the molecules,the open-circuit voltage(Voc)of organic solar cells based on compounds PM6:AP001 is as high as 1.03V and the maximum PCE is 1.65%.3.We design and synthesis naphthalene diimide polymers and application in organic solar cells.Generally compared with PDIs with multiple chemical modification positions,naphthalene diimides(NDIs)is modified with side chains.Hence,NDIs show more order arrangement,and the carrier mobilities are higher than that of PDIs.In this study,thieno[3;2-b]thiophene units was introduced into NDIs,two polymers AP004 and AP005 are synthesized by adopting BDT units which is a common building block in donors and NDIs polymerization.Compared with polymer acceptor AP004,the absorption spectra of AP005 is red-shifted about 30 nm,one of the main reasons are due to intruducing alkylthio side chains,which can improve the molecule’s solubility and adjust the molecular absorption spectra.The highest(PCE)of organic solar cells is 1.47%based on PM6:AP005.