A series of monodisperse macromolecules with A(2)-A(1)-D-A(1)-A(2) structure based on benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) BDT-4DPP, BDT-DPP-Rhod and BDT-DPP-CA were designed, theoretically calculated and synthesized, and compared with their parent molecules BDT-2DPP and BDTS-2DPP with A(1)-D-A(1) structure. These molecules possessed highly planar molecular geometries and high crystallinity. These molecules exhibited good thermal stability with decomposition temperatures of 322-388 degrees C, strong visible and near-infrared absorption (500-1000 nm), and HOMO energy levels of -5.38 to -5.19 eV and LUMO energy levels of -3.69 to -3.46 eV. Relative to the parent molecules A(1)-D-A(1), A(2)-A(1)-D-A(1)-A(2) molecules exhibited red-shifted and stronger absorption. The charge transport properties of these molecules were investigated by organic field-effect transistors, and their hole mobilities were 0.036-1.12 cm(-2) V-1 s(-1). Replacing alkyl with alkylthio on BDT led to mobility enhancement by one order of magnitude.
1.Peking Univ, Dept Mat Sci & Engn, Key Lab Polymer Chem & Phys, Coll Engn,Minist Educ, Beijing 100871, Peoples R China 2.Chinese Acad Sci, Inst Chem, Beijing Natl Lab Mol Sci, CAS Key Lab Organ Solids, Beijing 100190, Peoples R China 3.Capital Normal Univ, Dept Chem, Beijing 100048, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China