There are solar lights for use in small sheds.
A small solar panel is mounted on the roof to charge
a battery and the light is powered from the battery.
Here are two examples:
Solar Shed Light
Solar Shed Light

There are also roofing shingles that are actually solar panels.
They install and look similar to regular roofing shingles.
Wikipedia - Solar Shingles

As far as a paint that makes solar panels,
that technology has been around for decades.
You take a sheet of pure copper and clean one side of all tarnish.
It has to be extremely clean and bright copper.
Then you just paint that with copper-oxide paint.
Attach the power leads and you have a solar cell.
I have this book and it tells all about the process:
How to Build a Solar Cell That Really Works

And still there is always the option to just buy solar panel modules.
Building a solar electric generation system isn't too complicated.
It helps to have a working knowledge of DC electricity.

As I see it, making it easy is not the problem.
The problem is making it affordable.

Pooh Bear