Using a vertical titania (TiO(2)) nanotube array, an inverted polymer solar cell was constructed with power conversion efficiency up to 2.71%. In this study, self-organized TiO(2) nanotubes arrays were grown by anodizing Ti metal in glycerol electrolyte containing 0.5 wt% NH(4)F and 1.0 wt% H(2)O with 20 V potential. The tube length (∼100 nm) was controlled by the thickness of the sputtered titanium layer on the indium-tin oxide (ITO) substrate. The diameter of the tube was approximately 15-25 nm. After annealing in air at 500 °C for 1 h, nanotubes arrays were crystallized to the anatase phase from the initial amorphous state. Following the infiltration of polymeric semiconductor (poly(3-hexylthiophene) and (6,6)-phenyl C(60) butyric acid methyl ester, P3HT:PCBM), the filled TiO(2) layer had an optical absorption over a range from UV to visible light. The high surface-to-volume ratio of the nanotube arrays structure increased the effective area of the active region. The high efficiency of our solar cell is attributed to the vertical TiO(2) nanotube array's enhanced conduction of photo-induced current due to its charge transport capability.

By sputtering organic films with 10 kV, 10 nA C60+ and 0.2 kV, 300 nA Ar+ ion beams concurrently and analyzing the newly exposed surface with X-ray photoelectron spectroscopy, organic thin-film devices including an organic light-emitting diode and a polymer solar cell with an inverted structure are profiled. The chemical composition and the structure of each layer are preserved and clearly observable. Although C60+ sputtering is proven to be useful for analyzing organic thin-films, thick organic-devices cannot be profiled without the low-energy Ar+ beam co-sputtering due to the nonconstant sputtering rate of the C60+ beam. Various combinations of ion-beam doses are studied in this research. It is found that a high dosage of the Ar+ beam interferes with the C60+ ion beam, and the sputtering rate decreases with increasing the total ion current. The results suggest that the low-energy single-atom projectile can disrupt the atom deposition from the cluster ion beams and greatly extend the application of the cluster ion-sputtering. By achievement of a steady sputtering rate while minimizing the damage accumulation, this research paves the way to profiling soft matter and organic electronics.