For the purpose of this question I do not want to focus simply on the fact that there will be less "night time" for the panels while in orbit/outside the atmosphere of a planet.
What I'd like to focus on:
Understanding how much our atmosphere will actually absorb/deflect the incoming solar radiation. How much of a reduction in power are we looking in relation to AU? E.G. Would a solar panel on a plane halfway to the karman line see significant improvement in power? Is there any atmospheric composition in our solar system that would reduce the amount of solar energy available at the surface moreso than Earth?