A Melt-and-Seal Approach to Stable Perovskite Solar Cells

A tiny helper molecule that melts, flows, and then seals itself around perovskite solar cells. This clever "stepwise melting-polymerizing molecule" (SMPM) is like a tiny shield, protecting the cells from damaging humidity. During the cell-making process, SMPM goes through three stages: it melts from solid to liquid, spreads out to cover grain boundaries, and then self-polymerizes to create a hydrophobic barrier. This extra layer doesn't just keep water out; it also improves the cell's crystal structure, reduces energy waste, and aligns energy levels perfectly. The result? Perovskite solar cells that not only convert sunlight with high efficiency (up to 25. 21% for small areas and 22. 94% for larger ones) but also remain stable for over 2000 hours in humid conditions. Even without extra encapsulation, these cells can operate underwater, maintaining their structure and preventing lead leakage. This innovative SMPM strategy could be the key to making perovskite solar cells both stable and environmentally friendly for commercial use.