Controllable functionalization of single-wall carbon nanotubes by in situ polymerization method for organic photovoltaic devices

Single-wall carbon nanotubes (SWNTs) have been covalently modified with poly[(2-methoxy,5-octoxy)1,4-phenylenevinylene] (MO-PPV) by in situ polymerization reaction to form a series of nanocomposites with well-controlled interfaces. The method provided a mean to disperse nanotubes uniformly and maximize the interfacial area at the same time. Absorption spectrum and electron microscopy imaging of the composite structure have been influenced by doped a small amount of functionalized SWNTs. Moreover, steady-state and time-resolved photoluminescence spectra quenched markedly by the introduction of internal polymer/nanotube junctions within the polymer matrix. Photovoltaic devices based on MO-PPV/SWNTs bulk heterojunctions showed much better in performance. The data suggested that such improvement was attributed to the bulk molecular heterojunctions intrinsic nanophase separation that resulted more efficient excitons separation, transportation and collection.