Rutger Schlatmann also shared that HZB, together with Qcells, has achieved tandem cell efficiencies above 30% using TOPCon as the bottom cell. He emphasized that accurate measurement of tandem cells is critical and requires advanced metrology to ensure reliable results.
On the stability side, he highlighted some encouraging results. He said that HZB has one of the longest-running outdoor datasets, with small-area (1 cm²) cells deployed in 2019 and monitored since 2020. Despite the use of encapsulation methods available at the time, the cells showed good durability under outdoor conditions. Schlatmann also pointed out that several degradation mechanisms, such as decomposition, delamination, ion migration, and phase segregation, still need to be addressed.
Rutger Schlatmann, Head of the Solar Energy Division at Helmholtz Zentrum Berlin, opened his presentation by highlighting the role of perovskite tandem technology as the next efficiency frontier in photovoltaics. He noted that around 250 researchers at HZB are working on perovskite and next-generation cell technologies.
He explained that perovskite-based multijunction cells are gaining attention for their potential to achieve higher efficiencies, lower material usage, and reduced costs, while also enabling new application areas. Schlatmann also highlighted that perovskites have a tunable bandgap ranging from about 1.2 eV to over 2.0 eV, as well as strong electro-optical properties. This makes them well-suited for tandem applications, where increasing the number of junctions can further improve efficiency, with theoretical limits that reach well beyond those of current single-junction technologies.
We are now live with the TaiyangNews Next-Generation PV Technology Conference 2026, opening with Michael Schmela, Managing Director of TaiyangNews. The discussion begins with insights into emerging PV technologies and their path toward commercialization.
The TaiyangNews session today will walk us through the key developments in perovskite and tandem technologies. It brings perspectives from the R&D, materials, and manufacturing, with a focus on how these emerging concepts can progress toward commercialization.
The presentations will cover various advancements in cell technology, including potential for efficiency improvements, stability challenges, and scalability. The speakers will also touch on integration approaches, material innovations, and solutions for moving these technologies from the lab to mass production.
A key highlight of the event is the panel discussion titled When will the perovskite era truly start?, moderated by Shravan Chunduri of TaiyangNews. The panel brings together Chris Case from Oxford PV, Jerry Liao from Leadmicro, and Rutger Schlatmann from HZB. The panel will discuss the timelines for commercialization, key technical challenges, and what still needs to be addressed before perovskite-based technologies can scale.
Stay tuned as we begin shortly.
We are getting ready to go live with today’s TaiyangNews Virtual Conference, focusing on next-generation PV technologies and the pathways beyond the limits of conventional silicon. This conference will dive into the latest progress in perovskite and tandem solar cells, exploring solutions to key challenges in scalability, stability, and long-term reliability.
As the industry looks beyond incremental gains from single-junction technologies, today’s discussion brings together insights from R&D, materials, and manufacturing. These insights help to assess how these next-generation concepts can move perovskites toward commercialization.
Stay tuned for live updates as we begin at 9:30 CEST.
