Pv Cells operating on ambient light
PV cells do work in all levels of light (ambient light is enough to make my calculator work) BUT there are so many orders of magnitude difference in light intensity between indoors and outdoors that indoor operation gives a pathetic power harvest. You would be very hard pressed to recover one watt indoors with panels covering every wall, let alone the 10s of watts you would need for your LED requirement.

The current produced is more or less proportional to the light input. At a low enough light, the output voltage drops off as well and the conversion efficiency falls.