A team at Mahidol University in Thailand has developed a precision spray-coating technique for perovskite materials that can be used to build a multilayer perovskite solar cell.
The sequential spray deposition (SSD) process described in the Optical Materials Express journal under the title “Layer-by-layer spray coating of a stacked perovskite absorber for perovskite solar cells with better performance and stability under humid environment”, could be scaled up for mass production.
“Our work demonstrates a process to deposit perovskite layer by layer with controllable thicknesses and rates of deposition for each layer,” said research team leader Pongsakorn Kanjanaboos from the School of Materials Science and Innovation, Faculty of Science, Mahidol University in Thailand. “This new method enables stacked designs for solar cells with better performance and stability.”
So far, the solution processes typically used to make perovskites didn’t allow multilayer designs because the upper layer tends to dissolve the already-dried lower layer. After trying different spray coating methods, the researchers found one that worked at temperatures around 100°C, which they could use sequentially, one layer upon next, even with different perovskite compositions. They optimized the spray parameters to ensure that the tiny droplets dried and crystalized into solid perovskite immediately upon contact with the already-dried lower layer, preventing the formation of unwanted mixtures.