> Plants are more efficient in terms of energy generated per photon absorbed.

That is an incredibly misleading, since chlorophyl does not absorb all photons. It doesn't absorb any infrared, and is mostly transparent between 500 and 600 nm. So by that measurement, you're not counting about half of all sunlight that hits a plant. Silicon based solar may be less efficient per photon, but it absorbs everything from 800nm up to UV.

> but this could be fairly easily addressed when adapting the technology for a PV cell.

You mean DSSC cells? I suppose it's "easy" to demonstrate the effect in a lab under controlled conditions, but in real world applications, where they need to work for decades exposed to the environment, it stops being easy and becomes very, very hard. There's a reason you can't buy them.

They are also not projected to be more efficient than regular solar panels under sunlight, there's just hope that they might become cheaper.