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.
“With our spray coating process, the solution of the upper layer doesn’t disturb the solid film making up the first layer,” explains Pongsakorn. “Endless combinations of stacked perovskite architectures with any number of layers can be designed and created with precise control of thicknesses and rates of deposition for each layer.”
The researchers plan to use the new approach to make multilayer perovskite devices with new functions and combinations of performance and stability that were not possible before.
Mahidol University – https://mahidol.ac.th