Jiang S.,Huazhong University of Science and Technology |
Shi T.,Huazhong University of Science and Technology |
Long H.,Huazhong University of Science and Technology |
Sun Y.,Wuhan Jiawei Photovoltaic Lighting Co. |
And 2 more authors.
Nanoscale Research Letters | Year: 2014
A facile approach composed of hydrothermal process and annealing treatment is proposed to directly grow cobalt-manganese composite oxide ((Co,Mn)3O4) nanostructures on three-dimensional (3D) conductive nickel (Ni) foam for a supercapacitor electrode. The as-fabricated porous electrode exhibits excellent rate capability and high specific capacitance of 840.2 F g-1 at the current density of 10 A g-1, and the electrode also shows excellent cycling performance, which retains 102% of its initial discharge capacitance after 7,000 cycles. The fabricated binder-free hierarchical composite electrode with superior electrochemical performance is a promising candidate for high-performance supercapacitors. © 2014, Jiang et al.; licensee Springer.
Hu X.,Central China Normal University |
Heng B.,Central China Normal University |
Chen X.,Central China Normal University |
Wang B.,Central China Normal University |
And 4 more authors.
Journal of Power Sources | Year: 2012
Arrays of novel ultralong nanoporous ZnO nanobelts (NBs) are developed with a two-step synthesis strategy. This strategy combines two processes, a rapid hydrothermal synthesis of vertically aligned ultralong Zn(OH)F NB arrays directly on fluorine-doped tin oxide (FTO) at pH = 8.5 and conversion of a pyrolysis Zn(OH)F NB intermediate into nanoporous ZnO NB. Two factors play crucial roles in the rapid synthesis of ultralong Zn(OH)F nanobelt (NB) arrays, i.e., the pretreatment of the FTO substrate before entering the aqueous solution of Zn 2+ (2 M) and the presence of excess F - in the hydrothermal reaction solution. Upon the subsequent pyrolysis of the Zn(OH)F precursor at 500 °C for 2 h, ultralong nanoporous ZnO NB arrays are successfully generated. In addition, every NB is composed of a large number of nanocrystals and nanopores, which exhibit preferred orientation. Dye-sensitized solar cells (DSSCs) based on the ultralong porous ZnO NB arrays are assembled, and a high conversion efficiency (η) of 3.28% for a 27 μm thick film is obtained at 0.9 suns. This can be attributed to the high internal surface area and pronounced light scattering, as well as a good electron collection efficiency comparable with that of ZnO nanorod (NR)-based DSSCs. © 2012 Elsevier B.V. All rights reserved.
Zhou Y.,Central China Normal University |
Xia C.,Central China Normal University |
Hu X.,Central China Normal University |
Huang W.,Central China Normal University |
And 6 more authors.
Applied Surface Science | Year: 2014
Novel ZnO/SnO2 core-shell nanoneedle arrays were developed with a two-step synthesis strategy. The strategy combines two processes: a hydrothermal synthesis of a ZnO nanoneedle array and a coating of a SnO 2 layer on the surface of the ZnO nanoneedle. The addition of F - to the hydrothermal reaction solution played an important role in the formation of the ZnO nanoneedle array. The ZnO/SnO2 core-shell structure was successfully achieved after depositing a thin SnO2 layer on the ZnO nanoneedle by dip-coating. Dye-sensitized solar cells (DSSCs) based on ZnO/SnO2 core-shell nanoneedle arrays were assembled, and a high conversion efficiency (η) of around 4.71% was obtained at 0.9 suns. This can be attributed to the advantages of the core-shell structure. On the one hand, it affords a larger surface area for a more dye loading and light harvesting, which result in enhancing the photocurrent of the DSSC. On the other hand, the core/shell structure passivates nanoneedle surface defects for suppressing the recombination, which leads to the increase of the open-circuit voltage. Accordingly, the enhanced photocurrent and open-circuit voltage have led to a prominent increase in the photovoltaic efficiency of around 4.71%, which is much higher than that of an ordinary ZnO nanoneedle array-based DSSC. © 2013 Elsevier B.V.