Theres a theory that if you can combine boron, argon, gallium and indium into a solar cell it would be possible to harness 100% of the suns energy. Lets examine this statement at length.
Here are some things that you need to note before approving or refuting the claim. Argon is completely nonreactive (barring a few exotic states when its forced to react with fluorine and those are useless for solar panels as the light would destroy them. That said, from rudimentary chemistry knowledge, it seems possible that those elements could in fact be used in a particular way that would allow for efficiency of a solar cell. However, saying that they could harness 100% energy hitting the surface of the panel would be pushing it too far. As a matter of fact, the theoretical efficiency limit with infinite junctions and concentrated light is 86%. So no material combination can exceed that.