Synthesis And Properties Of Novel Conjugated Materials As Donors/acceptors For Organic Solar Cells

Heterojunction organic photovoltaics have been the subject of intensive academic interest overthe past two decades, and signifcant commercial efforts have been directed towards this area withthe vision of developing the next generation of low-cost solar cells. There are still many problems inthe field of donor and acceptor materials, such as the wide band-gap, the poor solubility, and thenarrow absorbance range. These problems can be solved by preparing innovative donor andacceptor materials and optimizing the structure of OPV devices.In donor aspects, the poly-hexylthiophene (P3HT) is introduced the benzothiadiazole groupsand3-hexylthiophene groups to build the branched doner-acceptor (D-A) structure. Throughincreasing the intramolecular charge transfer between units (ICT) and the conjugation between thebranch and main chain, it can get the narrow band-gap donor polymer. In acceptor aspects, a seriesof Naphthalimide（NDI）compounds are synthesized to be D-A structure non-fullerene smallmolecules, by being incorporated different electron-withdrawing groups. These materials have theexcellent solubility, strong absorbance and good carrier mobility. The branched D-A conjugationpolymer and non-fullerene small-molecule acceptor were fully characterized by NMR,MALDI-TOF MS, and GPC, et al.These studies have shown that the branched D-A conjugation polymers have narrow band gapand wide range of spectral absorption. The band-gap of polymer P3is1.75eV, and spectralabsorption range up to700nm above; non-fullerene small-molecule acceptors have good solubilityand wide spectral response range. These acceptors can be dissolved in common solvents, such astoluene, tetrahydrofuran, dichloromethane, etc, and the spectral absorption broke through the700nm.