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

Crystalline fullerene C70 microtubes (FMTs) were produced employing ultrasound-assisted liquid- liquid interfacial precipitation (ULLIP) technique at the interface between fullerene C70 solution in 1,2 dichlorobenzene (DCB) and isopropanol (IPA) at 15 degrees C. Using the vortex-flow motion of the subphase 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 ~5 times higher than that of the pristine C70. Moreover, the aligned FMT film showed better photovoltaics properties compared with randomly oriented FMTs and pristine C70 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.