Transparent solar cell absorbs only infrared and ultraviolet light. Visible light will pass through the cell unimpeded, so our eyes won't notice the present of the cell.
Previously, transparent cell had only achieved about 4% of efficiency. Researchers at University of California - Los Angeles (UCLA) have come out with a new design using 2 thin polymer solar cells that collect sunlight and convert it into electricity. The team has achieved an efficiency of 7.3%, which nearly double the efficiency.
Researchers led by Yang Yang, professor of engineering at UCLA, said the new cells could serve as a power-generating layer on windows and smartphone displays without compromising users' ability to see through the surface. The cells can be produced so that they appear light gray, green or brown, and so can blend with the color and design features of buildings and surfaces.
A single-layer solar cell absorbs only about 40% of the infrared light that passes through. The tandem device — which includes a cell composed of a new infrared-sensitive polymer developed by UCLA researchers — absorbs up to 80% of infrared light plus a small amount of visible light.
Transparent solar cell is ideal to be used on windows of tall buildings with limited roof space. One day, hopefully all of our windows will be integrated with transparent solar cells which could generate clean electricity to be consumed internally and exported to the grid to help curbing global warming.