Cheap and Super Efficient Solar Power Can Be Found in Perovskite Solar Cells

The future of super-efficient solar power can be found in the form of crystalline materials called hybrid perovskites, according to a new study released Monday.

Based on five years of research and development, researchers from  University of Utah in collaboration with the University of Texas at Dallas, the hybrid perovskite solar cells are now able to power conversion efficiencies that previously took decades to achieve with the top-performing conventional materials used to generate electricity from sunlight.

A study published in the Royal Society of Chemistry's Journal of Materials Chemistry A shows that the technique produces high-quality crystalline films with precise control over thickness across large areas, and could point the way toward mass production methods for perovskite cells.

Perovskites, a class of crystalline materials, have caused quite a stir in the clean energy world. Scientists and engineers have previously been unable to understand what exactly happens at the molecular level.

"People have made good films over relatively small areas -- a fraction of a centimeter or so square. But they've had to go to temperatures from 100 to 150 degrees Celsius, and that heating process causes a number of problems," said Nitin Padture, professor of engineering and director of the Institute for Molecular and Nanoscale Innovation.

According to the study, the perovskite photovoltaic devices can convert sunlight into electrical power with an efficiency of almost 20 percent; this is not as impressive as the 26 percent achieved by the best silicon cells, but perovskite photovoltaic devices can be manufactured at a fraction of the cost.

Yuanyuan Zhou, a graduate student in Padture's lab, wanted to see if there was a way to make perovskite crystal thin films without having to apply heat. He came up with what is known as a solvent-solvent extraction (SSE) approach.

"Using the other methods, when the thickness gets below 100 nm you can hardly make full coverage of film," Zhou said. "You can make a film, but you get lots of pinholes. In our process, you can form the film evenly down to 20 nm because the crystallization at room temperature is much more balanced and occurs immediately over the whole film upon bathing."

The researchers believe harnessing solar energy through photovoltaic cells has become easier with the development of hybrid perovskite.