The solar industry has always moved in waves – periods of steady progress punctuated by sudden leaps in technology. While it can take years or even decades for an innovation to fully mature, once it does, the shift is often swift, as manufacturers race to gain an edge.
The industry has seen this pattern before: the transition from multicrystalline to monocrystalline wafers, the adoption of bifacial cells and modules, and the rollout of large-format PV panels in both crystalline silicon (c-Si) and thin-film.
In c-Si PV cells, the transitions from p-type aluminum back-surface field (Al-BSF) to passivated emitter rear cell (PERC) and then to n-type tunnel oxide passivated contact (TOPCon) architectures have both pushed efficiencies higher and enabled lower solar system LCOE.
Each of these milestones reshaped the competitive landscape. Today, all signs point to another major technology shift looming on the horizon – one that doesn’t follow the pattern of incremental progress, but signals a true step change in how we produce solar.
An inline tester for perovskite PV from Eternal Sun.
Perovskite PV progress – rapid development underway
Since first being identified as a photovoltaic material in 2008, perovskites have achieved a remarkable leap in efficiency – from just 3.8% to more than 25% in single-junction devices. As a thin-film technology, PV perovskites are now being developed in research labs and by both startups and established manufacturers – an effort that could significantly reshape the future of solar manufacturing.
In the United States, momentum is building fast with more than 15 companies actively investing in perovskite PV technology. And they are making notable progress.
In March, San Jose-based Tandem PV closed its Series A round of $50 million, backed by both new and existing investors, including solar manufacturing veteran Tom Werner, the longtime CEO of solar technology pioneer SunPower. The company plans to use the funding to build a commercial-scale manufacturing line. Tandem PV reports having achieved a module efficiency of 28% and has a roadmap targeting 30% by the end of the year.
Fellow California startup Caelux has raised $75 million in equity funding since its founding in 2014 – with $58 million secured since 2022 alone. The company is currently operating a pilot line in Pasadena and, rather than scaling independently, is collaborating with established manufacturers to bring its perovskite-tandem technology to market.
Big names bet on perovskites
Established manufacturers with U.S. production are also advancing rapidly in perovskite development. In December 2024, Qcells announced a world-record cell efficiency of 28.6% for a c-Si-perovskite tandem on an M10-format wafer – an impressive achievement, especially given that the company reports that it only began commercial-scale tandem development the year before.
Meanwhile, in 2023 First Solar acquired Swedish developer Evolar and has since transformed the Uppsala facilities into its European R&D hub. In 2024, the company commissioned the 1.3-million-ft2 Jim Nolan R&D Center in Lake Township, Ohio, which features a full-scale module pilot line. The facility will support development of both single-junction and tandem thin-film modules and complements First Solar’s existing R&D operations in Santa Clara, California, and Perrysburg, Ohio.
When opening the facility, First Solar CEO Mark Widmar said in a statement: “Thin films are the next technological battleground for the solar industry because they are key to commercializing tandem devices, which are anticipated to be the next disruption in photovoltaics.” He noted that Chinese developers were closing “the innovation gap” with western rivals in thin-film technology.
Last year First Solar also signed a strategic partnership with German research institute ZSW to advance “all thin-film tandem technologies.” The institute has more than 30 years of thin-film technology experience. Areas covered in the research partnership include the “specialized characterization” required for tandem and thin-film technologies.
The ongoing challenge of perovskite characterization
Accurate characterization and long-term durability are emerging as critical hurdles on the path to commercializing perovskite solar technology. For investors and project developers to embrace the technology, they need reliable energy yield forecasts and confidence that the modules will endure real-world conditions, whether on the roof or in the field.
However, measuring the performance of perovskite PV has proven challenging. Unlike conventional c-Si PV cells and modules, perovskites respond differently to light exposure and IV testing, complicating efforts to generate consistent data. This has highlighted an urgent need for standardized testing protocols for both performance and stability. A draft IEC standard (60904-1-4) aims to address this gap by introducing formalized requirements, such as device pre-conditioning and the measurement of stabilized maximum-power output and other IV parameters, that go beyond current standards.
LED-based solar simulators play a vital role in the accurate characterization of perovskite solar devices for a number of reasons:
- The light spectrum can be precisely tuned to match the absorption profile of PV perovskites.
- They are suitable for prolonged light soaking, a process known to significantly affect perovskite power output.
- Their tunability helps address current mismatch between the c-Si and perovskite cells in tandem devices, enabling more accurate performance measurements.
Perovskite stability still presents a major hurdle
Assessing the stability of perovskite solar cells is currently centered on accelerated aging tests under light and elevated temperatures – crucial conditions, as light stability is fundamental to any viable PV material. The National Renewable Energy Laboratory (NREL) is at the forefront of this effort, leveraging its deep expertise in degradation mechanisms from decades of work on c-Si cells and modules to evaluate the true outdoor performance of perovskite devices.
In partnership with Sandia National Laboratories, NREL also leads the Perovskite PV Accelerator for Commercial Technology (PACT) program. PACT evaluates perovskite samples from various industrial partners under consistent conditions, generating comparative data on real-world outdoor stability – a key step in advancing commercial readiness.
While results still vary, significant progress has been made in extending the lifetime of perovskite modules thanks to advances in both encapsulation techniques and the intrinsic stability of the perovskite materials themselves. Notably, the first commercial perovskite modules have already entered the market, with lifetime guarantees exceeding 10 years.
However, accurately predicting long-term performance based on accelerated aging tests remains a challenge. As with earlier generations of c-Si modules, some degradation mechanisms may only become apparent under real-world operating conditions. New and more representative accelerated testing protocols will be needed. As field deployment of perovskite modules expands and R&D continues, we’ll gain a deeper understanding of these currently unknown degradation pathways, and how to mitigate them.
At Eternal Sun, we have built a strong track record in LED-based solar simulators, with over 100 systems deployed worldwide. In June, we expanded our capabilities by acquiring fellow LED-metrology pioneer Wavelabs, based in Leipzig, Germany.
“By combining the strengths of Eternal Sun and Wavelabs, we now offer one of the most comprehensive and advanced portfolios of solar simulators for perovskite PV,” said Erik Bentschap Knook, Eternal Sun’s chief commercial officer. “The portfolio now ranges from small-cell testers for research to dedicated inline tools for full-size module production.”
Given the complexity of perovskite characterization, the combined engineering expertise of Eternal Sun and Wavelabs positions the team to lead the way in delivering advanced, customized testing solutions for this rapidly evolving technology.
Peter Pasmans
Peter Pasmans joined Eternal Sun in 2024 as the Business Developer Perovskite Markets. He is an experienced solar technologist, having previously worked as an Applications Developer for backsheet materials supplier Endurans and Dutch chemicals giant DSM. He has a PhD in Physics from Eindhoven University of Technology.
Jake Veloza
Jake Veloza is an experienced business developer and leads sales for Eternal Sun in the United States. Before joining Eternal Sun, he worked in business development and sales for Massachusetts-based biotech company Thermo Fisher Scientific. In 2024 he completed an MBA, with a focus on Advanced Sustainability, at the Rotterdam School of Management.