(solar cells can be non-reflective black, the reflectivity is just to double-dip the suns rays)

I had no idea, thank you!

Such cells would be half as efficient I suppose, so would need to be twice as large and probably at least twice as heavy. I wonder how that might affect design and payload constraints as it scales.

Or you just wait twice as long, which seems fine for sleeper drones parked on a rooftop waiting for the target to come in range.