Biological impact of lead from halide perovskites reveals the risk of introducing a safe threshold

Abstract

Regulations currently in force enable to claim that the lead content in perovskite solar cells is low enough to be safe, or no more dangerous, than other electronics also containing lead. However, the actual environmental impact of lead from perovskite is unknown. Here we show that the lead from perovskite leaking into the ground can enter plants, and consequently the food cycle, ten times more effectively than other lead contaminants already present as the result of the human activities. We further demonstrate that replacing lead with tin represents an environmentally-safer option. Our data suggest that we need to treat the lead from perovskite with exceptional care. In particular, we point out that the safety level for lead content in perovskite-based needs to be lower than other lead-containing electronics. We encourage replacing lead completely with more inert metals to deliver safe perovskite technologies.

Fig. 1. Overview of the experiment of plants grown in perovskite-contaminated soils.

a Distribution of lead production worldwide in 2017 (open data from British Geological Survey). The inset shows the photo of mint plants grown in perovskite-contaminated soil within the campus of Fujian Agriculture and Forestry University, China (latitude 26.084, longitude 119.238). b The picture of mint plants grown on control soil (left) and c 250 mg kg⁻¹ Pb²⁺ perovskite-contaminated soil (right). The range of lead content measured in the leaves, stem, and root is reported on the side of each picture.

Fig. 2. Lead concentration in different parts of mint plants.

a Roots, b stems, and c leaves. The lead uptake ability (η, defined in Eq. 1) is reported in d. Data for lead concentration in leaves at 35.0 mg kg⁻¹ are not available (N/A) as plants did not produce enough leaves at such a high level of lead. The maximum, minimum, and mean value of each distribution are reported in a–c.

Fig. 3. Tin concentration in different parts of mint plants.

a Roots, b stems, and c leaves. The tin uptake ability (η, defined in Eq. 1) is reported in d. The maximum, minimum, and mean value of each distribution are reported in a–c.