In their paper , the researchers explained that most solar cells are currently silicon-based, which means that their efficiency is limited. This is what prompted them to examine the properties of barium titanate, a mixed oxide made of barium and titanium. 

“Ferroelectric means that the material has spatially separated positive and negative charges,” Akash Bhatnagar, co-author of the study, said in a media statement. “The charge separation leads to an asymmetric structure that enables electricity to be generated from light.”