Start making them!
Perovskite solar cells have been a promise like nuclear fusion for decades. Like cancer cures worked on in many research labs it feels like the stasis mechanism of academia is in full swing (this is the effect that a university can milk a concept or reinvent a thing many times, getting funds every time, because non-experts don’t know the state of the art). But as I have witnessed many times, even if a good product comes out of academic circles it can languish for decades and then fail to be burried under debt. The only thing that counts in innovation really is 1. Do banks like it and 2. Do banks like it. If they don’t they have many ways to kill it.
If a product disrupts bank cashflow it is killed, this is how banks remain dominant
Banks don’t like Perovskites because it requires little energy to make, uses an abundant raw material and can reduce demand for fossil fuels on its own power (meaning a prerovskite solar factory may produce perovskite panels without needing financing, leading to an explosion in production). This is my theory at least. So academics are closing every patentable loophole with great gratitude to their fianciers, to then NOT make any panels, which should be relatively easy, light weight, cheap. Academics don’t care, they move on to the next topic!
“The scientists showed the uncapped and capped solar cells as they are tested over periods up to 4,000 hours under different temperatures. The capped solar cell tested at 35 C showed zero efficiency losses after 3,551 hours.” (source)
“Tin-lead perovskite solar cell achieves 25.5% efficiency. The new NREL tin-lead tandem cell retained 80% of its maximum efficiency after 1,500 hours of continuous operation. “ (source)
“Ultralight flexible perovskite solar cells with 20.2% efficiency” (source)