@Hobbes' answer mentions that Deep Space 1 used special refractive solar concentrators attached to photovoltaic cells.
According to SCARLET:
The innovative array uses 720 lenses to focus sunlight onto 3600 solar cells, each converting the light into electricity to power the ion propulsion system and the rest of the spacecraft. The array produces about 2500 watts when at the same distance from the Sun as Earth. That may not sound like a lot (it's only enough to run 3 microwave ovens), but it's much more than most spacecraft exploring the solar system.
The NASA Spinoff article Concentrators Enhance Solar Power Systems says:
“Everyone remembers the ion engine on Deep Space 1, but they tend to forget that the SCARLET array powered it,” says Piszczor. “Not only did both technologies work as designed, but the synergy between the two, solar power and propulsion together, is really the important aspect of this technology demonstration mission. It was the first successful use of solar electric propulsion for primary propulsion.”
I can see some disadvantages; these bulk refractive lenses may add moe mass than simply covering the same area with photovoltaic cells, and they are probably more directional; after a certain amount of misalignment power would probably drop more rapidly than for a flat panel without focusing optics.
Why then did this mission use this technology instead of an equal area panel without 720 lenses?
"bonus points" for other examples where similar refractive concentrators were selected and used in space missions.