Incorporation of rubidium cations into perovskite solar cells improves photovoltaic performance

TLDR

Inorganic–organic perovskite solar cells suffer from poor long‑term stability due to UV light, humidity, and cation size constraints that hinder proper lattice formation. The authors use a water‑proof fluorinated polymer with UV‑absorbing pigments and incorporate rubidium cations into a cesium/organic lattice to enhance efficiency and stability. The resulting cells achieve >20 % efficiency maintained for over 500 h when protected by the polymer coating. References: Bella et al., Saliba et al., Science, this issue, pp.

Abstract

Improving the stability of perovskite solar cells Inorganic-organic perovskite solar cells have poor long-term stability because ultraviolet light and humidity degrade these materials. Bella et al. show that coating the cells with a water-proof fluorinated polymer that contains pigments to absorb ultraviolet light and re-emit it in the visible range can boost cell efficiency and limit photodegradation. The performance and stability of inorganic-organic perovskite solar cells are also limited by the size of the cations required for forming a correct lattice. Saliba et al. show that the rubidium cation, which is too small to form a perovskite by itself, can form a lattice with cesium and organic cations. Solar cells based on these materials have efficiencies exceeding 20% for over 500 hours if given environmental protection by a polymer coating. Science , this issue pp. 203 and 206