Monojit Bag

Every battery or supercapacitor has an unassuming player — the polymer glue. It binds the active material particles together and helps them stick to the current collector. Previously, it was considered just inert mass: it's there, as long as it doesn't get in the way. But in this work, the glue takes center stage.

In a thin perovskite film, a material for cheap solar cells, light creates pairs of charges: an electron and a "hole." They need to reach the electrodes and produce current, but many vanish along the way. Where exactly they go is the question that determines how efficient the cell will be.