So, the team ... got efficiencies in the area of 33 to 34 percent. They also sent a sample to a European test lab, which came out with an efficiency of 33.7 percent. The researchers have a few ideas that should boost this to 35 percent, but didn't attempt them for this paper. For comparison, the maximum efficiency for silicon alone is in the area of 27 percent, so that represents a very significant boost and is one of the highest perovskite/silicon combinations ever reported.
Love this research and I hope solar eventually beats ICE engines for efficiency.
However....
The crystals were reasonably stable when simply exposed to light. But the combination of light and heat caused a more significant decay in performance. The researchers say that "devices maintain ≥90 percent of their initial performance up to 1,000 hours," but a decay of up to 10 percent in about three months is not ready for commercial deployment. So, still some work to do there.