Dye-Sensitized Solar Cells Based on Anatase TiO₂ Nanoparticle/Nanowire Composites

Abstract

Dye-sensitized solar cells were fabricated based on the composites of anatase TiO2 nanoparticles and single crystalline anatase TiO2 nanowires. Nanoparticle/nanowire composites can possess the advantages of both building blocks, i.e., the high surface area of nanoparticle aggregates and the rapid electron transport rate and the light scattering effect of single-crystalline nanowires. Three different composites were prepared with 5 wt %, 20 wt %, and 77 wt % nanowires, respectively. The performances of composite solar cells were compared with pure nanoparticle cells at a series of film thickness. With low nanowire concentrations (5 wt % and 20 wt %), the composite films maintain similar specific surface area as the pure nanoparticle films, while the composite cells show higher short-circuit current density and open-circuit voltage. An enhancement of power efficiency from 6.7% for pure nanoparticle cells to 8.6% for the composite cell with 20 wt % nanowires has been achieved under 1 Sun AM1.5 illumination (100 mW/cm2). For the composite film with 77 wt % nanowires, the nanowires became the major phase. Their less compact packing resulted in significant decrease of the specific surface area, and thus the current density. However, with the increase of film thickness, the current density showed a continuous increase in the whole thickness range up to 17 microm, indicating the improved electron diffusion length due to the formed nanowire network. The nanowires also helped to preserve crack-free thick films. These results show that employing nanoparticle/nanowire composites represents a promising approach for further improving the efficiencies of sensitized solar cells.

Energy production and conversion applications of one-dimensional semiconductor nanostructures

“…For the TiO 2 system, a 20% (by weight) NW content increased the PCE to 8.6% from 6.7% for the pure NP-DSSC [38]. For the ZnO system, the mixed NP-NW mercurochrome-sensitized DSSC saw an improvement of PCE from 0.45% (pure NP) to 2.77% (V oc = 0.58 V, J sc = 8.33 mA cm -2 , FF = 0.58) using 5.5 μm-long NWs [39].…”

First-principles study of thinTiOxand bulklike rutile nanowires

“…More insight about the stability and bonding nature of these nanowires can be provided by examining three isomers of B4 structure. B4a is uniform B4 in which d 2-4 = d [4][5] . Next isomer is shaped by forming Ti-Ti dimers, so B4 nanowire gains very small energy ͑about 10 meV͒ with respect to the B4a structure.…”

“…In recent years, one-dimensional ͑1D͒ TiO x nanostructures 3 such as nanorods, nanowires, and nanotubes have been investigated extensively because of their size and morphology dependent structural, chemical and electronic properties. They lead to a significant number of technological applications including gas and humidity sensors, 4 dye-sensitized solar cells, 5,6 photovoltaics, and photocatalysis. 7 TiO 2 nanowires [8][9][10][11][12][13] can be synthesized on TiO 2 surfaces or in zeolites.…”

Preparationand Characterization of Rutile-anatase Hybrid TiO2Thin Film by Hydrothermal Synthesis

“…Recently, various types of nanostructured TiO2 such as nanoparticles, nanotubes, nanowires, and nanorods have been prepared and adopted as electrode materials to improve the performances of DSSCs [21][22][23][24][25]. Tan et al [26] synthesized TiO2 nanoparticles attached to TiO2 nanowires to increase the surface area and applied them as a DSSC electrode material. They reported that the resulting DSSC had a powerconversion efficiency of 8.6%, which is 2% higher than the efficiency of the cell with a TiO2 nanoparticle electrode.…”