The photocatalytic activity of nanostructured semiconductor films has been widely explored in designing solar cells, solar hydrogen production, and environmental remediation. Of particular interest is the dye-sensitized solar cell (DSSC) which uses nanostructured titanium dioxide films modified with sensitizing dyes. Despite the initial success of achieving 10% solar conversion efficiency, the effort to further improve their performance has not been very successful. A major hurdle in attaining higher photoconversion efficiency in such nanostructured electrodes is the transport of electrons across the particle network. The photogenerated electrons in nanostructured films for example have to travel through the network of semiconductor particles and encounter many grain boundaries during the transit. Such a random transit path for the photogenerated electrons increases the probability of their recombination with oxidized sensitizer. With the recent advance in the design of nanotube and nanowire architecture, it should be possible to use such one-dimensional nanostructures to direct the flow of photogenerated charge carriers. The obvious challenge is to use nanowire or nanotube networks as support to anchor light-harvesting semiconductor particles and facilitate the electron transport to the collecting electrode surface in a solar cell. Researchers now have demonstrated that single wall carbon nanotube (SWCNT) architecture when employed as conducting scaffolds in a titanium dioxide semiconductor based photoelectrochemical cell can boost the photoconversion efficiency by a factor of 2.
With an increased focus on alternative sources of cheap, abundant, clean energy, solar cells are receiving lots of attention. Harnessing the power of the sun to replace the use of fossil fuels holds tremendous promise. One way to do this is through the use of solar, or photovoltaic, cells. Until now, solar cells that convert sunlight to electric power have been dominated by solid state junction devices, often made of silicon wafers. Thanks to nanotechnology, this is now being challenged by the development of a new generation of solar cells based on thin film materials, nanocrystalline materials and conducting polymeric films. These offer the prospects of cheaper materials, higher efficiency and flexible features. This has opened up new opportunities in solar cell research and development and, consequently, there is considerable investor interest in solar nanotechnology startups. Both inventors and investors are betting that flexible sheets of solar cells used to harness the sun's strength will ultimately provide a cheap and efficient source of energy.
A group of Chinese researchers prepared dye-sensitized solar cells using micro/nanocomposite TiO2 porous films, resulting in cells with enhanced light collection. They applied a technique which can produce a large area in continuous fabrication. This technique opens an alternative way for manufacturing solar cells on an industrial scale.
With an increased focus on alternative sources of cheap, abundant, clean energy, solar cells are receiving lots of attention. The dye sensitized solar cell (DSSC) is one of the most important developments in photovoltaics in the last two decades. Researchers are now on the brink of improving the efficiency of DSSC through nanowires.