Because the title says "1000x more powerful than existing panels". The article clarifies that this is existing barium panels, but the title (I would argue misleadingly so) does not clarify that they aren't referring to existing silicone solar panels.

Especially misleading because of the use of the word "existing" because it sounds like they're referring to something that has made it out of a lab, but I'd wager 99.99999+% of people have never seen an "existing" barium solar panel.

A less misleading title would be something like:

Experimental barium solar panel 10000x more efficient than past attempts, possibility of performance parity with silicon in sight

Or some such nonsense. You could move the second half to a subtitle and still be much clearer and less misleading than the original in title alone.