Nature study reports 1,000 hour damp heat stability in 28 percent perovskite silicon tandem cells

Researchers at King Abdullah University of Science and Technology and Helmholtz Zentrum Berlin report perovskite silicon tandem solar cells that pass 1,000 hours of damp heat at 85 degrees Celsius and 85 percent relative humidity with less than 5 percent power loss. The paper, published today in Nature, lists Stefaan De Wolf at KAUST and Steve Albrecht at HZB as corresponding authors and reports stabilized efficiencies near 28 percent on 1 square centimeter devices.

The result targets a central barrier to commercial deployment. Passing the IEC 61215 damp heat protocol is a requirement for bankability, and few tandems have met that threshold without large efficiency losses.

Methodology and findings The team combined surface passivation at the perovskite interface with a low damage recombination contact and improved moisture barriers. They used a thin 2D perovskite capping layer to suppress ion migration and nonradiative recombination, then deposited a transparent conductive recombination layer with reduced plasma exposure to protect the perovskite top cell.

For packaging, the devices used laminated glass with edge seals and a multilayer polymer barrier. The authors report that unencapsulated cells degraded rapidly under heat and humidity, while encapsulated cells retained more than 95 percent of initial power after 1,000 hours. Light and elevated temperature induced degradation tests showed slower efficiency loss when the 2D capping and contact stack were both applied.

The study does not claim module scale stability or 25 year outdoor lifetime. It reports laboratory devices and mini modules under accelerated aging, and it notes failure modes under ultraviolet exposure that require further mitigation.

Industry context Perovskite silicon tandems are moving from pilot lines into early manufacturing. Oxford PV began shipping tandem products in Europe, and First Solar acquired perovskite know how through its 2023 Evolar deal to explore tandem pathways. Large Chinese manufacturers have signaled interest in tandem lines once stability and yield improve.

If replicated at larger area with acceptable yield, the reported stack design could simplify qualification for field trials on rooftops and utility sites. It gives equipment makers and encapsulant suppliers concrete targets for moisture ingress and plasma damage control, which are directly actionable in existing PV manufacturing lines.