A pinch of capsaicin , the active component in hot peppers (Capsicum), can be a secret ingredient for more stable and efficient perovskite solar cells.
That’s what a new study by Chinese and Swedish researchers suggests.
Polycrystalline solar cells
While metal halide perovskite semiconductors represent a promising component for next-generation solar cell technologies, they are plagued by non-radiative recombination, an undesirable process at the electron level that reduces efficiency and increases heat losses. The researchers looked for an additive to mitigate these effects .
Because of the burning sensation it produces in the mouth, capsaicin is commonly used in food products to make them spicier. But the study also suggests that spraying capsaicin on lead methylammonium triiodide perovskite precursor (MAPbI3) during the manufacturing process leads to a greater abundance of electrons to conduct current on the semiconductor surface.
This addition of capsaicin resulted in polycrystalline MAPbI3 solar cells with the most efficient charge transport : control devices showed an energy conversion efficiency of only 19.1%, devices containing capsaicin had an efficiency of 21.88 %.
The improved solar cells also showed improved stability, maintaining more than 90% of their initial efficiency after 800 hours of storage in ambient air .
Capsaicin also greatly reduced the defect density of the perovskite film, increasing electron density by an order of magnitude and increasing charge transport.
While capsaicin may provide a low-cost and widely available additive for future development of highly efficient perovskite solar cells, the stability of the material must be further refined before it is ready for commercial applications .