Every time I see a headline about perovskites solar cells, I ask “what’s the longevity?” Efficiency is nice, but it doesn’t mean anything when perovskites degrade hard in less than a year.
The idea would be that they’re so cheap that we can plaster them on any surface that gets a bit of sunlight. Higher efficiency is better than lower efficiency, of course, but it’s not such a big deal when they’re so damn cheap. But they have to last.
This article doesn’t even seem to answer the longevity question.