Science study sets durability and lead-leakage benchmarks for perovskite–silicon tandem solar cells

A team from the University of Oxford, Oxford PV, and Helmholtz‑Zentrum Berlin reports in Science today that perovskite–silicon tandem cells passed extended damp‑heat stress and released limited lead under simulated glass break with lead‑scavenging encapsulants. The authors measured power retention over 2,000 hours at 85 degrees Celsius and 85 percent relative humidity, and quantified lead in water after intentional module fracture, outcomes that speak directly to reliability and environmental risk.

The most immediate impact is a test protocol that engineers can adopt now. The paper details encapsulation stacks and phosphate‑based scavengers that kept dissolved lead below typical drinking water limits in bench‑scale break tests, alongside a failure analysis workflow that links ion migration and interfacial degradation to measurable power loss.

The study, led by senior authors Henry Snaith at the University of Oxford and Steve Albrecht at Helmholtz‑Zentrum Berlin, pairs in situ photoluminescence and impedance spectroscopy with IEC 61215‑style stress. The group reports less than 5 percent power loss for perovskite–silicon tandem minimodules after 2,000 hours of damp heat, and identifies interlayer chemistry that suppresses halide migration under bias.

The authors measured lead release by immersing fractured glass–glass laminates in deionized water and hard tap water, then analyzing effluent with inductively coupled plasma mass spectrometry. Encapsulants with embedded phosphate resins and ionomers cut dissolved lead by more than 90 percent versus standard EVA films in like‑for‑like stacks.

For policymakers, the data address a core regulatory question. The work compares measured lead release to thresholds used in EU water directives and provides a method to verify containment after impact. That gives standards bodies a starting point for perovskite‑specific modules rather than extrapolating from silicon norms.

For manufacturers, the paper translates lab degradation chemistry into bill‑of‑materials guidance. It highlights barrier layer thickness, cation choice in the perovskite, and electrode adhesion as the dominant levers for damp‑heat survival, and shows how those choices interact with module lamination temperature and cure time.

The authors caution that outdoor field data over multiple seasons remain necessary. They also note that the lead‑scavenging approach adds material cost and must be validated at full module scale.

If adopted, the methods could narrow the gap between record‑cell performance and bankable products. That would help investors evaluate claims from perovskite startups and inform utility procurement rules, as tandem architectures move from pilot lines into early deployments.