Solar energy would be the best energy source: cheap, renewable and non-contaminant.

Now, after 10 years of research, a new solar cell technology developed by Massey University's Nanomaterials Research Centre could generate electricity from sunlight at a 10th of the cost of current silicon-based photo-electric solar cells.

The team led by Dr Wayne Campbell has achieved an array of colored dyes employed in dye-sensitized solar cells.

The synthetic dyes represent simple organic chemicals resembling those encountered in nature.

The green dye is synthetic chlorophyll similar to that employed by the plants in photosynthesis.

Other investigated dyes imitate hemoglobin, the red pigment of the blood.

"Unlike the silicon-based solar cells currently on the market, the 10x10cm green demonstration cells generate enough electricity to run a small fan in low-light conditions - making them ideal for cloudy climates. The dyes can also be incorporated into tinted windows that trap to generate electricity." said Campbell.

"The green solar cells are more environmentally friendly than silicon-based cells as they are made from titanium dioxide - a plentiful, renewable and non-toxic white mineral obtained from New Zealand's black sand. Titanium dioxide is already used in consumer products such as toothpaste, white paints and cosmetics." he said.

"The refining of pure silicon, although a very abundant mineral, is energy-hungry and very expensive. And whereas silicon cells need direct sunlight to operate efficiently, these cells will work efficiently in low diffuse light conditions. The expected cost is one 10th of the price of a silicon-based solar panel, making them more attractive and accessible to home-owners."

The researchers say they got the most efficient porphyrin (a pigment implied in photosynthesis) dye in the world and want to improve the cell construction and performance before developing the cells commercially.

"The next step is to take these dyes and incorporate them into roofing materials or wall panels. We have had many expressions of interest from New Zealand companies," said the Centre's new director, Professor Ashton Partridge.

"The ultimate aim of using nanotechnology to develop a better solar cell is to convert as much sunlight to electricity as possible. The energy that reaches earth from sunlight in one hour is more than that used by all human activities in one year".