A group of Researchers from the National University of Singapore managed to develop a low temperature method to synthesize ZnO nanostructures that combine nanoparticles and nanowires.
“In this study, we have successfully employed both ZnO nanowires and nanoparticles in a single device, a combination that reaps the benefits of both nanostructures,” said two members of the research team, Moe Kevin and Ghim Wei Ho.
The sunlight is absorbed by these dyes which send electrons to the ZnO nanowires. Then, the electrons accumulated in nanowires will diffuse to the anode. ZnO nanoparticles have larger surface areas than ZnO nanowires and they are not very effective electron transporters.
The research team explained that they made the nanoparticles penetrate the spaces between the nanowires, by aligning the them perpendicularly to the substrate and reducing their density.
So, using these monocrystalline ZnO nanowires, having excellent electron transport properties, the scientists have provided a direct and very fast route for electrons to be collected. “This is essential in ensuring efficient separation of electrons and holes before recombination can occur,” said Moe Kevin and Ghim Wei Ho.
Researchers have also mentioned that ZnO nanostructures can significantly improve the light harvesting and electron transport rate. They also explained how those structures can be created using low-temperature synthesis.
“In addition, low temperature synthesis allows for the production of PV devices on conducting plastic substrates which are both lightweight and flexible. This opens many new possibilities of implementing PV devices at the consumer level.”, said Ho and Kevin.