Solar-induced self-assembly of TiO2-beta-cyclodextrin-MWCNT composite wires

Wire-like TiO2-beta-cyclodextrin-MWCNT composites have been successfully fabricated through a solar-induced self-assembly process. The wires were stable for more than several months both in water and under air in dry conditions. The composites were characterized in detail by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, Raman spectra and Raman mapping. The results revealed that the wires with a mean diameter of 1 microm were uniform. MWCNT and beta-cyclodextrin can interact with each other, which was confirmed in our previous research, meanwhile, monodisperse TiO2 nanoparticles can also associate with beta-cyclodextrin. Thus, beta-cyclodextrin molecules acted as linkers between MWCNT and monodisperse TiO2 nanoparticles. A reasonable mechanism was also proposed to explain the formation of this wire. Furthermore, the dye-sensitized solar cells were assembled with a sandwich-structured electrode containing the wires and they exhibited an enhanced power conversion efficiency. This may be attributable to the compact composite-structure of the wires and the unique electronic properties of MWCNT, which favor the transportation of photogenerated electrons.