Can the solar panels available be coated with a material (to improve it's looks) and not alter it's efficiency?
No. The only coatings I am aware of are those that reduce reflection so more light gets through the protective surface to the actual cells. Anything thing that affects appearance is going to be reflecting light back to the viewer and the photons of that light are not available for electricity or heat. If the appearance of the panels offends you, then they need to be concealed by a fence of panels around them that do not throw shadows on the panels.
