A solar cell is a device that converts solar energy into electricity. Recent developments in solar cell technology have made possible lower manufacturing costs with acceptable energy-conversion efficiency. Applications not possible before like utilization in fabric or thin-coating to a number of surfaces can now be achieved. 

Be honest: who has never dreamed to become invisible? To go everywhere, to look at everything without being seen, just a dream. The invisibility is a subject of comics (the invisible woman in the Fantastic Four for ex.) and movies (the cloak used by Harry Potter to be hidden from the enemies).