The breakthrough technique, known as Ostwald ripening process, uses a methyl ammonium bromide (MABr) treatment that helped make the PV cell – a hybrid halide concept – "more efficient and reliable with higher reproducibility".
The scientists, funded under the US SunShot initiative, converted a low-quality perovskite film with pinholes and small grains into a high-quality film without pinholes and with large grains, ratcheting up the efficiency to 19% via the MABr treatment, which involves dissolving small crystals and then redepositing then onto larger crystals.
