Synthesis And Properties Of Copolymers Of Benzodipyrrolidone And Naphthodithipohene

Polymer solar cells(PSCs)have received widespread attention as a promising resource due to their unique advantages in obtaining low-cost,lightweight,large-area,and flexible devices.In the past ten years,great efforts have been made in low gap band(LGB)polymers and their typical bulk heterojunction(BHJ)devices,increasing the power conversion efficiency(PCE)from about 1% to more than 12%.The low-energy end absorption spectrum used as a solar material to cover the entire visible and near-infrared region as much as possible is necessary condition for improved solar energy utilization.The narrow band gap polymer material not only has a wide absorption in the short-wave range,but also has a wide absorption in the long-wave range,especially in the near-infrared region.There are two ways to reduce the energy gap of a polymer: one is to have a donor-acceptor structure in the polymer backbone to enhance its intramolecular charge transfer ability,and the other is to increase the length of the conjugated structure of the polymer.In this thesis,benzodipyrrolidone is used as the acceptor unit and naphthodithiophene is used as the donor unit.A series of donor-acceptor(D-A)polymers are designed and synthesized,and their structures and properties are studied.(1)D-A polymers formed by copolymerization of benzene ring modified benzodipyrrolone derivative and naphthodithiophene.A series of acceptor-donor polymers(PBDPP-NDT,PBDPP-NDT-A10,PBDPP-NDT-A20,PBDPP-NDT-A30)were synthesized using 3,7-dithiophen-2-yl-1H,5H-pyrrole[2,3-f]indole-2,6-dione(BDPP)as the acceptor unit,1,6-bis(trimethyl)Tin)-4,9-bis(decyl)-naphthodithiophene(NDT)as the donor unit,and 1,4-dibromo-2-dodecylthiophene as the third monomer.The structures of monomers and polymers were characterized by nuclear magnetic resonance and other means,and the UV-visible absorption properties,electrochemical properties and thermal properties of monomers and polymers were systematically studied.Research have shown that the wavelength absorption range of the four polymers is 340-700 nm,and the long-wave absorption peaks are 567 nm,536nm,431 nm,and 600 nm,respectively.Polymers with different molecular spatial structures can affect the charge transfer ability in the molecule,that is,molecular chain regularity The more flexible polymer PBDPP-NDT has a narrower optical energy gap than that of the poor molecular chain regularity polymer PBDPP-NDT-A10.The optical energy gaps of the four polymers are1.65 eV,2.05 eV,and 2.21 eV,respectively.1.64 eV.The electrochemical energy gaps are1.67 eV,2.08 eV,2.23 eV,1.61 eV,respectively.And the polymer exhibits excellent thermal stability,and the thermal decomposition temperature is above 380?.(2)D-A polymers formed by copolymerization of thiophene-modified benzodipyrrolone derivative and naphthodithiophene.A series of acceptor-donor polymers(PBDPT-NDT,PBDPT-NDT-A10,PBDPT-NDT-A20,PBDPT-NDT-A30)were synthesized using 3,7-thiophene-2-yl-1H,5H-pyrrole[2,3-f]indole-2,6-dione(BDPT)as the acceptor unit,1,6-bis(trimethyl)Tin)-4,9-bis(decyl)-naphthodithiophene(NDT)as the donor unit,and 1,4-dibromo-2-dodecylthiophene as the third monomer.The structures of monomers and polymers were characterized by nuclear magnetic resonance and other means,and the UV-visible absorption properties,electrochemical properties and thermal properties of monomers and polymers were studied in detail.Research have shown that polymers with BDPT as the acceptor unit exhibit better performance.The polymer wavelength range is 350-1100 nm,the long-wave absorption peaks are 722 nm,742nm,730 nm,718nm,and the optical energy gap is 1.12 eV.,1.09 eV,1.16 eV,1.20 eV.The electrochemical energy gaps are 1.08 eV,1.13 eV,1.19 eV,1.25 eV,respectively.The thermal decomposition temperature is above 384?.