Inspite of the high cost, solar cells are widely used.

Explanation

A special grade silicon is used for making solar cells and silver is used for interconnection of cells in panel.
`rarr` This makes the solar cells expensive.
`rarr` But it converts solar energy into electricity and about 0.7 W of electricity is produced when exposed to the Sunlight.
`rarr` Solar cells and panels are widely used in artificial satellite, space probes like Mars orbiters, wireless transmission systems, radio or TV relay stations, traffic signals, calculators and in many toys.
`rarr` At domestic level, maximum use of solar energy can be achieved by using solar roof top thus saving electricity.
So, solar cells are widely used.