The next generation of solar cells and devices are on the way, which could replace the dominant solar panels on the market today—those made with silicon. One of the most promising materials are perovskite crystals and now researchers from Los Alamos National Laboratory, Northwestern University and Rice University have figured out a way to flip the orientation of the crystals in solar devices. They recently published their findings in the journal Nature.
“Crystal orientation has been a puzzle for more than two decades, and this is the first time we’ve been able to flip the crystal in the actual casting process,” explained Hsinhan Tsai, a Rice graduate student at Los Alamos. Tsai is working with senior researcher Aditya Mohite and is lead co-author of the study in Nature. “This is our breakthrough, using our spin-casting technique to create layered crystals whose electrons flow vertically down the material without being blocked, midlayer by organic cations.”
The researchers were looking to create a perovskite solar cell that works better than 3-D perovskites. Perovskites have shown the ability to convert more than 20 percent of the sun’s light into electricity but still, experience poor performance in stress tests. The new research is looking into two-dimensional materials.
By tweaking crystal production methods the researchers at Los Alamos and the universities developed a new type of two-dimensional, layered perovskite crystals in which they’ve been able to control how crystals line up on a layer that’s an atom thin. That’s allowed them to more than triple the power conversion efficiency of the materials they’re researching.
The recently published research builds on research conducted at Northwestern, where Professor Mercouri Kanatzidis and PhD Costas Stoumpos created the two-dimensional material. They were investigating a 2-dimensional material that orients its layers perpendicular to the substrate. However, the cells were operating at a 4.73 percent efficiency because they were out of alignment. Now, by aligning the materials they have achieved a 12 percent conversion efficiency.
“The 2-D perovskite opens up a new dimension in perovskite research,” said Kanatzidis. “It opens new horizons for next-generation stable solar cell devices and new optoelectronic devices such as light-emitting diodes, lasers and sensors.”Tweet