The silicon photovoltaic cell that's so common today was "discovered" in 1954 by researchers at Bell Telephone Laboratories. For many years PV panels were so expensive that only the U.S. military and marijuana growers in California could afford them. But that has certainly changed now. PV cells & the PV panels that you commonly see on roof-tops are now inexpensive enough that they are being used to supply electricity to third-world villages. It's been a wild ride - but the good news is that PV is now an electrical energy generation source "contender".
And PV's future is bright! And Clean! And Renewable! And (even more) Affordable!
The "Photovoltaics" document below, as well as the "PV in Detail" document below that, will give you a solid introduction to this "exciting" technology.
(select the document window & scroll thru the pages)