Sweeping claims don't automatically preclude improvements.
For example consider a patent claiming a combination of round disks with central holes, and long circular rods. and a second sweeping claim where the first part of claim one includes all round objects.
If you invent the pneumatic tyre , you haven't infringed on the wheel patent just because your tyre is round. Neither have you infringed on the beach ball patent (it's round and filled with air). Your invention is clearly novel, and useful, and not immediately obvious from the prior art.
Broad sweeping claims need to be read in the context of the primary claim. So in the example above, if you make your wheels from oak instead of pine, and put the nails in at an angle, and paint them green, then they are still round things that function as wheels. So the broad sweeping claim is intended to pick up the obvious things like changing the color.
Patented inventions describe the means to achieve a specific end. But, if you can arrive at the same end by using different (and novel and non obvious) means, then the means is patentable, you will probably have to re-use some elements of the other patent, (like screws, and wire and bits of brass) but there is no infringement if these items were re-used in obvious and well known ways.
Also be wary of broad sweeping claims that try to tie down the end use but not the means to get there.
So for your solar example (I'm assuming you meant silicon, as making PV cells from a rubbery silicone polymer would certainly be revolutionary), "making electricity from sunshine" is talking about the end , tossing the word silicon in there doesn't make a broad claim enforcable. The claim needs to indicate a specific process or manufacturing step, that for example [improves the capture of sunshine into the cell] or [improves the quantum efficiency] or [improves the way the electricity is extracted]. Also the PV effect is a natural process, so you can't patent that, only applications utilising the effect.
