from wiki: Perovskite materials such as methylammonium lead halides are cheap to produce and simple to manufacture. Solar cell efficiencies of devices using t

from wiki: Perovskite materials such as methylammonium lead halides are cheap to produce and simple to manufacture. Solar cell efficiencies of devices using these materials have increased from 3.8% in 2009 to 22.1% in early 2016,[3] making this the fastest-advancing solar technology to date --------------- 22% efficiency and cheap materials?