From an engineering standpoint, it it blocks 2% of solar radiation as stated by the article (and let's suppose we can send that amount of stuff in space) it will have to reflect that amount of solar radiation, not absorb a significant amount of it (because of heating and dissipation) and direct anything it absorbs away from Earth as much as possible.
Now we've just got a "sail maintenance" problem: we put the sail up, continue to burn ff now unimpeded by the worst side effects. 1-2 decades later, if the sail were to fail / lose funding / get neglected by temporary geopolitical conflict, earth rapidly accumulates all of carbon debt we accrued.
The bigger problem with absorption is potentially heating the material to the point of vaporization.
All that said, the most practical form of this would probably be something like a fresnel lense that uses refraction or a structure that uses diffraction to redirect the light rather than reflect or absorb it.