Perovskite solar cells (PSCs) are promising solar technologies. Although low-cost wet processing has shown advantages in small-area PSC fabrication, the preparation of uniform charge transport layers with thickness of several nanometers from solution for meter-sized large area products is still challenging.

Imagine catching a comet.
Comets are clusters of frozen gases passing close to the Earth at high speed, whose fate is to gradually evaporate until disappearing.