With all these magic coatings, one has to ask - how do you safely get the electricity out? Even if you could make a coating that generated 240V AC at 50Hz (which isn't theoretically impossible, just very difficult) how can you use it? Health and safety issues? Durability? Practicality? I strongly suggest to focus on something less esoteric for the time being. And if you look at the links Artur suggested, the spray on process is actually part of a conventional solar cell, which of course is a well known, and often quite complex, structure.
yes sir whatever you are suggesting is completely true. But if we consider the case of solar panels which are not affordable. The reason behind asking a question is to develop voluntary techniques for making coating which converts solar energy into electricity. whatever artur suggested is really thought provoking because by advancing that technique we can definitely make it.