| With the development of human society,more and more researchers focus on energy issues.Semiconductor materials can not only utilize the solar energy for the production of hydrogen from water to provide a clean energy source,but also can utilize organic photovoltaic technology to convert solar energy into electricity Therefore,One of the keys to the Energy crisis and environmental pollution is to explore semiconductor materials with high efficiency.The disadvantages of traditional semiconductor materials,such as high cost,low light response range,and low light absorption efficiency,greatly limit its applications.Organic semiconductor materials not only have the diverse molecular structures,but also retain good flexibility and the optical absorption wavelengths of adjustability.Thus,Organic semiconductor materials cover the shortages of traditional semiconductor materials and become a research hotspot.Studies have shown that constructing donor-acceptor conjugated polymers with alternating conjugated units of electron-rich donor units（D）and electron-poor acceptor units（A）is an effective ways to achieve highly efficient organic semiconductor materials.A large number of new organic conjugated polymers,which are applied to enhance apparent quantum yield（AQY）for H2 from water and organic photovoltaic property are reported at present.We designed a series of monomers with different structures and prepared a series of benzodithiophene conjugated polymers through Suzuk-Miyaura coupling reaction and Stille coupling reaction.Then we characterize these polymer materials and studied their photocatalytic hydrogen production and fluorescent sensing properties.this article focuses on the following aspects:（1）Three new donor-acceptor（D-A）type of conjugated microporous polymers（CMPs）,with 4,8-dithiophene-benzo[1,2-b:4,5-b’]dithiophene as donor unit and benzothiadiazole and its derivatives were used as acceptor units,were synthesized through palladium-catalyzed Suzuki polymerization,which named PDBD-BT,PDBD-FBT and PDBD-DFBT.The resulting polymers exhibit excellent thermal stability with decomposition temperature up to 280 oC and the introduction of fluorine atoms in the backbone of the polymer PDBD-DFBT leads to a significant red shift in the UV absorption wavelength.The optical band gap drop down to 2.09 eV,and the apparent quantum yield（AQY）for H2 of PDBD-DFBT improved to 2.8μmol/h.（2）Two new donor-acceptor（D-A）type of linear conjugated polymers,with benzo[1,2-b:4,5-b’]dithiophene（BDT）as donor unit,were synthesized through palladium-catalyzed Stille polymerization,which named PBDT-P and PBDT-BP.The resulting polymers exhibit a broad absorption spectrum（from 350 nm to 550 nm）and excellent thermal stability with decomposition temperature up to 400°C.The introduction of biphenyl in the backbone of the polymer PBDT-BP leads to 52 nm red shift in the UV absorption wavelength.The apparent quantum yield（AQY）for H2 of of PBDT-BP increases to 9.7μmol/h.（3）Two new donor-acceptor（D-A）type of conjugated polymers,with4,8-（2-octylthiophen-5-yl）-benzene[1,2-b:4,5-b’]dithiophene,and benzo[1,2-b:4,5-b’]-dithiophene（BDT）as dontors unit and 3,7-bis（2-bromo-3-（2-mercaptotetradecyl）-thiophene）-naphthalene[1,2-c:5,6-c]bis[1,2,5]thiadiazole（DTNT-DTBr）was used as acceptor units,were synthesized through palladium-catalyzed Stille polymerization,which named PTBDT-DTNT and PBDT-DTNT.The resulting polymers exhibit excellent thermal stability with decomposition temperature up to 280 oC and low band gap about1.3 eV.PTBDT-DTNT has a HOMO level at-5.28 eV,which is the proper HOMO in idealized Polymers.The highest achievable PCE for PTBDT-DTNT is 8.25%. |
