Perovskite may leak less lead than lead-solder silicon, say scientists

Researchers led by the Huazhong University of Science and Technology modeled lead flows from perovskite photovoltaics in China from 2026 to 2060. They found that, under best-practice conditions, cumulative lead leakage could be up to 94% lower than from crystalline silicon modules using lead-based solder at the same installed capacity.

The study combines dynamic material flow analysis with freshwater ecotoxicity modeling. It tests four perovskite scenarios (business as usual, cleaner production, technology advancement, and best practice) against two silicon cases, with and without lead solder, and assumes perovskites reach 20%, 40%, or 60% of the market by 2060. The researchers used an AI forecasting model to project China’s cumulative PV capacity, reaching about 6,781 GW by 2060. They normalized results by both installed capacity and electricity output, and reported the same relative reductions under each.

The comparison reflects both differences in lead content and assumptions about leakage during manufacturing, use, and end-of-life management. Data compiled by the researchers put single-junction perovskite modules at about 2 grams to 3.9 grams of lead per kilowatt, and all-perovskite tandems at about 3.6 grams to 4 grams, against about 36 grams to 53 grams per kilowatt for silicon modules with lead solder.

In the 40% market-share scenario, cumulative lead leakage from 2026 to 2060 reaches about 479 metric tons under the perovskite best-practice scenario, against about 8,554 metric tons for silicon with lead solder. Under business as usual, perovskite leakage reaches about 2,406 metric tons, more than the roughly 1,848 metric tons modeled for silicon with lead-free solder. The cleaner-production, technology-advancement, and best-practice perovskite scenarios all come in below the lead-free silicon case by 2060.

Manufacturing dominates modeled lead losses under business as usual. In that scenario, cumulative lead input to the perovskite life cycle reaches about 29,200 metric tons, and 58.9% of it is lost, mainly during manufacturing. The researchers assumed that perovskite modules break at 2% a year, against 0.1% for silicon. Perovskite lifetimes start at about 10 years and rise to 20 years by 2060 in the business-as-usual and cleaner-production scenarios, and to 30 years in the technology-advancement and best-practice scenarios.

The study also models the effect of Chinese exports, 45% of which went to Europe in 2022-24. Under the modeled trade scenarios, developed economies would effectively outsource manufacturing-stage leakage, while tropical developing countries would face domestic leakage up to three times higher than the upstream leakage tied to their imports, because of faster module degradation and limited recycling. The researchers estimate Brazil’s downstream leakage at about 119 metric tons against about 50 metric tons upstream, and Germany’s at about 17 metric tons against about 67 metric tons upstream.

The researchers concluded that lead does not have to be a prohibitive barrier to perovskite commercialization, provided governance shifts from material restrictions toward transnational extended producer responsibility. No such transnational scheme exists for PV.

In the European Union, solar panels are excluded from the lead limits of the EU Restriction of Hazardous Substances Directive, but are covered by the Waste Electrical and Electronic Equipment Directive, which requires producers to finance collection and treatment and sets targets of 85% recovery and 80% reuse and recycling for collected panels.

Concerns about lead have dogged perovskites since their emergence, but real-world evidence is starting to build. In separate outdoor tests published in the Royal Society of Chemistry journal EES Solar, hail-damaged glass-glass perovskite-silicon tandem devices released about 0.07% of their lead over nine months. However, commercial deployment remains limited: Oxford PV shipped its first perovskite-silicon tandem modules in 2024, while GCL and UtmoLight have reported gigawatt-scale lines in China.

The scientists described their findings in “Overstated Lifecycle Lead Risks of Perovskite Solar Cells and the Hidden Transboundary Displacement,” which was recently published in Environmental Science & Technology.