Vortex-Aligned Ordered Film of Crystalline Fullerene C70 Microtubes with Enhanced Photoluminescence and Photovoltaics Properties

Crystalline fullerene C-70 microtubes (FMTs) were produced employing ultrasound-assisted liquid-liquid interfacial precipitation (ULLIP) technique at the interface between fullerene C-70 solution in 1,2 dichlorobenzene (DCB) and isopropanol (IPA) at 15 degrees C. Using the vortex-flow motion of the sub-phase water (also called Vortex-Langmuir-Blodgett technique), the FMTs were aligned and homogeneous films were prepared at the air-water interface. The aligned FMTs film exhibited enhanced photoluminescence (PL) with PL intensity similar to 5 times higher than that of the pristine C-70. Moreover, the aligned FMT film showed better photovoltaics properties compared with randomly oriented FMTs and pristine C-70 film obtained from the spin coating. The compact, directional orientation and proper surface coverage of the FMT film enhanced the charge transport properties in the photovoltaic device.