The ink could also be coated onto silicon to create perovskite/silicon tandem solar cells.
High-throughput roll-to-roll fabrication would make printing solar cells in a similar process to printing newspapers.
Some of the best-performing spin-coated PSCs combine the perovskite with a poly(triarylamine) (PTAA) transport layer, but PTAA is hydrophobic and highly repellent to liquid perovskite ink. Adding a surfactant to the ink formulation overcame the repellence, resulting in better quality interface and films and better device performance, Subbiah says. The team also switched the ink to a lower-boiling solvent, reducing ink drying time without the need for further processing steps.
Optimized slot-die coated PSCs captured solar energy at 21.8 percent efficiency, a significant improvement over the 18.3 percent previously recorded for PSCs made this way.
The ink could readily be coated onto textured silicon to produce a perovskite/silicon tandem solar cell. The frstslot-die coated silicon-perovskite monolithic tandem solar cell had a 23.8 percent efficiency.