14 DAY TRIAL // Harvesting solar energy is a clever way to make use of a clean and renewable fuel. You don't need to dig the ground for it, there are no pipes and powerplants, and best of all, it's ecological. Unfortunately, existent solar cells are not too efficient and can't convert more than 10 percent of the solar energy into electricity of heat and they don't exactly come cheap, either.
A new technique developed by Researchers at the Advanced Technology Institute (ATI) at the University of Surrey can process thin film silicon using an UV laser. This could mean new devices, like solar cells and control circuits displaying improved performances at lower costs.
Dr Damitha Adikaari is the lead investigator and says that: "The use of a modified laser pulse shape results in more efficient transformation of amorphous silicon into its crystalline form, with significant control of surface roughness allowing for higher degree of control of design parameters."
It's exactly the knowledge of pulse profile and its effect on the silicon texture that allowed the scientists to create efficient organic/inorganic hybrid solar cells, with the highest reported efficiency for nanocrystalline silicon and the type of polymer used (MEH-PPV).
"The cells were initially fabricated to help us understand nanocrystalline inorganic/organic interfaces, made with laser textured nanocrystalline silicon and spin-cast MEH-PPV. However, they result in impressive photocurrents, where the bulk of the photo-generation is believed to be from the nanocrystalline silicon layer," commented Dr Adikaari.
The Director of the ATI, Professor Ravi Silva, who also heads the Nano Electronics Centre where the work was carried out, comments: "The fundamental understanding we have gained in nano-texturing of amorphous silicon has led ATI researchers to improve charge extraction of organic/inorganic hybrid devices, which is giving rise to some exciting device physics. These nano-engineered devices promise a lot of potential for large scale organic/inorganic photovoltaics."
Solar cells are regarded as one of the key technologies towards a sustainable energy supplies and are mainly used in situations where electrical power from the grid is unavailable, such as in remote area power systems, Earth-orbiting satellites and space probes, handheld calculators or wrist watches, remote radiotelephones and water pumping applications.