The panel discussion, moderated by Shravan Chunduri of TaiyangNews, explored how close perovskite tandem technology is to commercialization. Rutger Schlatmann rated the technology around 6 out of 10, while Chris Case noted that it is already viable for shorter-lifetime applications but not yet ready for 30-year warranties. Jerry Liao added that the technology is progressing, but the market is still small and several challenges remain.
Regarding efficiency, the panel noted that while record cells are approaching 35%, translating these results into large-area modules remains difficult. Stability under real operating conditions remains a key issue, and the gap between lab performance and commercial scale is still significant.
From a manufacturing perspective, equipment and process standardization are still evolving. Liao highlighted that, unlike TOPCon, perovskite involves multiple process pathways, which slows down scaling. The panel also discussed options for the bottom cell, noting that while HJT offers advantages like built-in TCO, existing TOPCon capacity cannot be ignored, and simpler architectures are preferred to keep complexity low.
On materials, the panel addressed the use of lead, noting that the amount is small, manageable, and difficult to replace without compromising performance.
When it comes to scaling, capital is available but often constrained by risk-averse investment decisions. The need for a clear cost-per-watt advantage and stronger market demand was highlighted as critical for large-scale adoption.
Looking ahead, the panel expects tandem technology to start reaching meaningful volumes toward the end of this decade, with early adoption in specific applications. Ultimately, all speakers agreed that market demand will be the key driver for commercialization, as a strong market would enable investment, scaling, and faster progress.
Chris Case from Oxford PV pointed out that standards for perovskite technologies are still catching up. He said that the current reliability frameworks were originally designed for technologies such as CIGS and CdTe, so they don’t fully capture perovskite behavior. He stressed that these devices need to be tested under more realistic conditions, such as MPP, continuous light exposure, and higher temperatures, to properly understand how they degrade over time.
On the manufacturing side, he noted that progress is already being made in scaling to large-area production, with equipment and even turnkey solutions becoming available, particularly from Asia. Case also highlighted the role of patents, noting Oxford PV’s strong portfolio and recent licensing efforts to support wider commercialization of the technology.
Menglei Xu, R&D Director at JinkoSolar, presented the company’s progress in perovskite-silicon tandem technology. He highlighted that achieving high Voc is critical for reaching higher efficiencies in tandem cells. Jinko has developed a perovskite-silicon tandem cell with an efficiency of 34.76% using an industrially fabricated TOPCon bottom cell.
He also referred to a recent collaboration with partner universities, in which several developments at the cell and module levels were addressed, and multiple tandem results combining perovskite with TOPCon were also presented.
On the roadmap, JinkoSolar remains open to different materials and cell architectures as the technology evolves. While most current results are still at the R&D stage, Xu noted that a pilot line for tandem production could be expected within the next 3 years, followed by GW-scale manufacturing in about 5 years.
Lukas Ziegler from WAVELABS highlighted that measuring tandem solar cells is more complex than measuring silicon cells. Accurate measurement requires precise spectrum control and preconditioning using steady-state illumination to stabilize the cells before IV testing. Fast IV sweeps can introduce hysteresis and metastability, making results less reliable. He noted that current tandem measurement accuracy is around ±3%, and standards require that the spectrum be adjusted based on EQE, meaning conventional xenon flashers are no longer sufficient.
Hangzhou First's Bo Jin presented the company's encapsulation solutions for perovskite-based solar technologies, including the TPO encapsulant XUR150 and the high-barrier sealant PIB-405.
The materials have undergone reliability testing and shown stable performance under damp heat (DH) and humidity freeze (HF) conditions, with minimal yellowing. In particular, PIB-405 demonstrated less than 5% power degradation even under extreme conditions of 85°C and 100% relative humidity.
The company offers encapsulation solutions for different configurations, including perovskite-only, 2T tandem, and 4T tandem modules. It also provides 0BB foil for use in 0BB perovskite cells and modules.
Kaien Chang, VP of Technology at Solamet, discussed the key challenges and progress in low-temperature metallization pastes for perovskite tandem cells. Key challenges include bulk resistance and contact formation. Solamet is developing 2 types of low-temperature pastes – thermoplastic and thermoset – that are being tested on different substrates using ITO and IZO as transparent conductive oxides (TCOs), with ongoing collaboration with customers to further improve contact resistance. In addition, a laser transfer process, developed in collaboration with DR Laser, is being used to achieve finer-line metallization with silver-coated copper powders.
Yongqiang Zhang from S.C New Energy discussed the key challenges and solutions for the mass production of perovskite-silicon tandem solar cells.
One of the main challenges is maintaining a clean surface on the silicon bottom cell. To address this, the company uses functional water with micro- and nano-sized bubbles (below 100 µm) to improve cleaning effectiveness. Another challenge is achieving high-quality film formation on textured silicon surfaces. For this, vacuum coating technologies such as PVD with both low- and high-temperature evaporation are used. Other methods, such as ALD and CVD, are also being explored as alternative deposition techniques. Film formation also faces issues such as edge effects and deflection. To overcome this, inkjet printing is used for depositing the perovskite layer.
Jerry Liao, CTO of Leadmicro, presented the company’s work on equipment solutions for next-generation cell manufacturing, with a strong focus on improving the stability of perovskite solar cells.
Stability remains one of the key challenges for perovskite technology, with degradation caused by factors such as humidity, oxygen, temperature, and light exposure. In addition, the presence of metal electrodes causes metal atoms to diffuse into the perovskite layer, while ion migration can lead to corrosion, resulting in the formation of AgI.
To address these challenges, Leadmicro is working on atomic layer deposition (ALD) as a solution. ALD can be used to form both electron- and hole-transport layers. For tandem cells, ALD-deposited SnO₂ can act as an encapsulation layer, preventing direct contact between silver and the perovskite layer, while also serving as a carrier buffer layer.
Bin Fan, Founder and Chairman of GCL Perovskite, presented the company’s approach to tandem technology, focusing on the comparison between 2-terminal (2T) and 4-terminal (4T) architectures.
He explained that 4T designs offer greater flexibility, as they can operate efficiently across a wider bandgap range of 1.4 to 2.2 eV, whereas 2T architectures achieve peak performance only in a narrow bandgap of around 1.73 eV. This wider tolerance allows 4T to fully utilize the design space of perovskite materials. He also noted that while 2 T systems could incur an annual energy yield loss of about 7%, 4T systems avoid this limitation. He added that 4T can also offer advantages in manufacturing.
Highlighting GCL’s progress, Fan shared that the company has achieved a world-record tandem module efficiency of 29.51% on a 2,048 cm² module and 27.06% on a near-commercial size module of 1.71 m².
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.