Perovskite solar cells have promised to push photovoltaic efficiency to new heights for years. Now, with major manufacturers achieving crucial reliability milestones and the first large-format modules entering large-scale production, the technology is moving beyond the laboratory. But as the race to bring perovskites to market accelerates, a fundamental question remains: will production processes deliver on cost, efficiency, and durability?
This week, host Jonathan Gifford speaks with two leading manufacturers pursuing different approaches to perovskite-silicon tandem solar technology at the Perovskite Connect 2026 event in Berlin.
First, Fabian Fertig, head of R&D PV technology at Qcells, discusses the company's breakthrough in achieving independent certification for its two-terminal tandem modules – a significant step towards commercial viability. Fertig explains why reliability, rather than record-breaking efficiency, has been the real challenge, and how Qcells is preparing to scale production to gigawatt scale.
But the best route to commercialization is not yet locked in.
Frank Mu, head of sales Europe at GCL Perovskite, makes the case for the four-terminal approach to tandem modules. With GCL already delivering its first large-scale orders in China, Mu explains why the company believes its architecture offers advantages in manufacturing scalability, material stability, and real-world performance. He also discusses the practical challenges of bringing these modules to market, from simplifying electrical connections to overcoming moisture-related failures and proving long-term durability.
With two industry heavyweights backing competing technologies, the race is about both high conversion efficiency alongside reliability, and manufacturing an affordable product that can be supplied at scale. And if perovskites can meet those demands, the next major transformation of the solar industry may happen faster than many expect.
About The smarter E Podcast
The smarter E podcast is all about the current trends and developments in a renewable, decentralized and digital energy industry. Our host welcomes and interviews personalities who shape our industry and drive developments forward. A new episode is published bi-weekly on Thursdays.
Fabian Fertig is a PV technologist with managerial, strategic, and technical experience in PV technology with expertise including TOPCon, PERC and perovskite/silicon tandems, with a current focus area in solar for terrestrial and space applications. Before joining Qcells in 2016 he was a Researcher at Fraunhofer ISE for six years. He took over leadership of Qcells Germany’s tandem R&D. He has a PhD from the University of Freiburg.
Frank Mu is a solar industry professional who joined GCL Perovskite in 2015 as the company’s first employee in Europe. He is responsible for understanding market requirements, establishing partnerships and to prepare for commercialization of perovskite tandem modules. Before joining GCL Perovskite worked at Baywa r.e. as a purchasing manager and team lead. He studied at the Universities of Auckland and Freiburg.
