Flexible carbon nanotubes/TiO2/C nanofibrous film as counter electrode of flexible quasi-solid dye-sensitized solar cells

Flexible counter electrode (CE) is a key to develop flexible dye-sensitized solar cells (DSSCs). To obtain flexible CE with well electro-catalytic activity, the carbon nanotubes (CNTs) were employed to modify the flexible TiO 2 /C nanofibrous film. All the CNTs/TiO 2 /C nanofibrous film with incorporation of CNTs into TiO 2 /C nanofiber showed pleasurable flexibility. In addition, the specific surface area, the conductivity, and the electro-catalytic activity of the nanofibrous film increased as the content of CNTs increased, reaching the largest values before decreasing. The CNTs/TiO 2 /C nanofibrous film with 2% of CNTs incorporation possessed optimal electro-catalytic activity. Therefore, the conversion efficiency of the flexible quasi-solid DSSCs based on the nanofibrous film CE was greatly enhanced and the highest conversion efficiency of about 3.4% was achieved. Besides, the properties of the CNTs/TiO 2 /C nanofibrous film almost remained constant after 50 cycles with the bending radius of 1 mm and the twisting angle of 10π, implying that it exhibited excellent bending stability and twisting stability. The flexible CNTs/TiO 2 /C nanofibrous film has a huge potential in flexible devices.