Lead-free perovskites
Hybrid perovskite solar cells

The growth and commercialization of perovskite solar cells could be limited by the toxicity of the lead contained in the perovskite materials used as light absorbers. This toxicity is primarily linked to the formation of soluble compounds such as PbI₂ and PbBr₂. A solar module contains between 0.3 and 0.8 g of Pb per square meter. If, following a leak, all the lead from a 1-square-meter module were to end up in the soil, the impact of this pollution can be calculated. Assuming a soil depth of 15 cm and a density of 1.3 g/cm³, this represents a mass of 195 kg of soil, and thus a maximum increase in lead content of 4.1 mg/kg. This value remains low compared to the background lead content in uncontaminated soil, which ranges from 10 to 40 mg/kg. The recommended limit for residential soil is a maximum of 200 mg/kg. However, the form in which lead is released (local concentration,...