In this letter, the authors report a dye-sensitized solar cell (DSSC) using a ZnO-nanoflower film photoanode, which was grown by a hydrothermal method at 95°C. The dye used was cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II) bis-tetrabutylam-monium (N-719). At AM1.5G irradiation with 100mW∕cm2 light intensity, the DSSC based on ZnO-nanoflower film showed an energy conversion efficiency of 1.9%, which is much higher compared to that (1.0%) of the control device constructed using a photoanode of upstanding ZnO-nanorod array fabricated by hydrothermal method as well. The better performance of ZnO-nanoflower DSSC was due to a better dye loading and light harvesting of the ZnO-nanoflower film. The results demonstrate potential application of ZnO-nanoflower array for efficient dye-sensitized solar cells.

We reported an efficient inverted bulk-heterojunction ͓regioregular of poly͑3-hexylthiophene͒: ͑6,6͒-phenyl C 61 butyric acid methyl ester͔ solar cell with a highly transparent sol-gel derived ZnO film as electron selective layer and MoO 3 as hole selective layer. By modifying the precursor concentration of sol from 0.75 to 0.1M, the optical transmittance of ZnO film increases from 75% to 95%. This improvement in transmittance increases the short-circuit density of inverted solar cell from 5.986 to 8.858 mA/ cm 2 without sacrificing the open-circuit voltage and fill factor of the device. We also demonstrated that the device incorporated with MoO 3 has a larger open-circuit voltage and fill factor than the device without MoO 3. Power conversion efficiency of 3.09% was achieved under simulated AM 1.5G illumination of 100 mW/ cm 2 .