Stick a PV panel in the window. You could do it right now. I don't think its worth doing, but if you think this is a good idea there's nothing stopping you.

There's plenty of sensible efficient places we could stick more photovoltaics before its worth the resources chasing the tiny power output this is going to provide. Ultimately this is as silly an idea as solar freakin roadways for all the same reasons.

That's like the most logical approach. I don't care if it only charges a phone or keeps a few led lights on... Please keep the heat out.