doi:10.1038/nindia.2013.165 Published online 11 December 2013
Researchers have fabricated efficient dye-sensitized solar cells by depositing cactus-like interconnected zinc oxide nanoparticles and two dyes on a modified glass substrate . These solar cells are very promising for harnessing solar energy with high efficiency.
Dye-sensitized solar cells have been found to be a feasible, ecofriendly and low-cost alternative to conventional solar cells. However, existing methods for making such solar cells require using high temperatures. Room-temperature synthesis of the materials used to fabricate these solar cells is still a challenge.
To meet this challenge, the researchers synthesized zinc oxide films on a fluorine-doped, tin-oxide-coated glass substrate. They dipped the glass substrate coated with a zinc oxide film in zinc acetate dehydrate (an organic compound) and ammonia and then heated it in air. This resulted in the formation of interconnected nanoparticles having a cactus-like structure. Next, they fabricated solar cells by loading the nanoparticles with two dyes — metal-free indoline D149 dye and ruthenium-metal N719 dye.
The light-harvesting efficiency of the solar cells was evaluated by exposing them to ultraviolet and visible light. The researchers found that metal-free indoline D149 dye showed a good response to light illumination, resulting in a power conversion efficiency of 3.43 per cent. In contrast, the ruthenium-metal N719 dye exhibited a comparatively low response to light under similar conditions.
The interconnected cactus-like nanoporous structure had a high surface area, which enables high concentrations of dye to be loaded onto its surface and in its pores. This is advantageous for realizing fast electron transport and results in better light harvesting than commercially available nanoparticles.