The UK-based perovskite solar PV specialist has announced a new metrology research project with Swansea University and a new development agreement with Renolit, a German plastic films, sheets and polymer solutions company.

Power Roll, a UK-based perovskite solar PV specialist, has announced a new metrology research project with Swansea University and a joint development agreement with Renolit, a German plastic films, sheets and polymer solutions company, which will begin with an outdoor field trial in Germany.

In the U.K., samples of Power Roll's patented flexible, micro-groove perovskite solar PV film will be provided to researchers at Swansea University and the National Physical Laboratory in a six-month feasibility project to support the development of inline and end-of-line testing tools for perovskite solar cells.

It also involves the development of stability guidelines for industry standards. Without these advancements, perovskite solar cell companies “could face significant hurdles in achieving product accreditation,” noted the company.

“The project will support scalable roll-to-roll manufacturing of lightweight perovskite PV, delivering commercial prototypes, testing protocols, and an invited academic review to strengthen UK capability in advanced semiconductor photovoltaics,” Nathan Hill, Power Roll Senior Scientist, told pv magazine.

It entails assessment of standards, metrology techniques, equipment, routes to characterize large scale devices and artificial intelligence (AI) pertaining to monitoring during manufacture.

In December, Renolit and Power Roll announced an 18-month joint development agreement that will begin with an outdoor trial of the UK company’s micro-groove perovskite prototypes on a Renolit building façade in Germany.

The initial deployment will be one to two square meters. There are plans to scale it up in size and power capacity as the project progresses, according to Hill.

“The purpose is to monitor and validate real-world performance and durability, and to understand the potential of the micro-groove solar technology,” Neil Spann, Power Roll CEO, told pv magazine.

Renolit has a commercial interest as a potential supplier of certain film layers to Power Roll, but also to explore integrating Power Roll's solar film into its existing building materials product lines, and to explore the potential of manufacturing under license in Europe, according to Spann.

Power Roll has also completed tests of smaller devices at its headquarters.

Renolit France, the French branch of the German company, recently launched a new PVC-based mounting product for rooftop PV systems.

Power Roll, founded in 2012, has proven its technology and manufacturing process, and secured 27 patent families.

Researchers in South Korea improved the performance of tin monosulfide (SnS) solar cells with a potassium fluoride-assisted post-treatment and a vapor transport deposition process. The treated solar cells had a power conversion efficiency of 4.10% and reduced recombination sites, compared to 3.42% for untreated devices.

Research led by Chonnam National University in South Korea has improved the performance of tin monosulfide (SnS) solar cells with a potassium fluoride-assisted (KF) post-treatment and a vapor transport deposition (VTD) process. The treated solar cells had a power conversion efficiency of 4.10% and reduced recombination sites, compared to control devices.

The research topic is complementary to the research group's earlier germanium oxide (GeOx) interlayer study, which achieved a 4.81% cell efficiency, according to first author of the research, Rahul Kumar Yadav.

“The KF treatment enhances the intrinsic quality of the SnS absorber surface, providing a superior foundation for subsequent interface engineering, while the GeO_x interlayer optimizes band alignment and suppresses recombination at the rear contact,” Kumar Yadav, told pv magazine.

“In our ongoing work, we are actively combining KF surface treatment with GeO_x back interface engineering, as we expect their integration to deliver further gains in voltage, operational stability, and overall device efficiency,” he added.

In the study, the researchers varied the concentration of KF solution to measure the effect of drop-cast KF surface treatment on the structural, morphological, and photovoltaic properties of VTD-SnS absorber layers.

Testing showed that the KF treatment enhanced “film uniformity, densification, and wettability.” Devices based on the optimized KF-treated SnS absorber had a PCE 4.10%, an improvement compared to 3.42% for untreated devices, with further analysis revealing reduced recombination sites.

“The KF-assisted solution post-treatment functions as a surface modulation step, improving grain connectivity, reducing surface roughness, and passivating electrically active defects,” said Kumar Yadav, adding that the resulting higher open-circuit voltage and fill factor, enabled enhanced efficiency “without altering the overall device architecture.”

The researchers concluded that the research represents a “scalable strategy to overcome key interfacial limitations” and to advance SnS thin-film photovoltaics.

Also participating in the study were Korea Aerospace University and Kyungpook National University.

The work is detailed in “Modulating surface morphology via potassium fluoride-assisted solution post-treatment enables VTD-SnS thin film solar cells to achieve over 4% efficiency,” which appears in Materials Today Energy.

Looking ahead, the group is focused on developing SnS thin-film solar cells beyond the 4% efficiency threshold “through coordinated absorber surface, heterojunction interface, and rear interface engineering, while maintaining compatibility with scalable manufacturing processes,” said Kumar Yadav.

A Chinese-Swedish research team has boosted the performance of tin-lead perovskite solar cells by modifying additives and post-treatment processes. The device also demonstrated improved stability, retaining 60% of its initial efficiency after 550 hours at 85 °C under maximum power point conditions.

Researchers from East China Normal University and Sweden’s Linköping University have developed an alternative passivation method for tin-lead (Sn-Pb) perovskite solar cells that improves both efficiency and stability by avoiding the use of tin fluoride (SnF₂). The approach combines a lead fluoride (PbF₂) post-treatment with lead powder in the precursor.

“We identified and elucidated a previously unrecognized factor that drives the photo-thermal instability of Sn-Pb perovskite solar cells,” Wenxiao Zhang, co-first and co-corresponding author of the research told pv magazine, explaining that the study established that SnF₂ “parasitic reactions” trigger perovskite decomposition and degradation of functional device layers.

“Whereas the markedly lower stability of Sn-Pb perovskites relative to their Pb-only counterparts is usually ascribed solely to the oxidation of stannous ion (Sn²⁺), antioxidant strategies alone have failed to deliver a substantial improvement in photothermal durability. This work pinpoints the underlying cause and proposes an effective alternative,” said Zhang.

“To avoid the adverse effects of SnF₂ on stability and hole transport, we replace SnF₂ additive with lead powders, known for its antioxidant and crystallization-regulating effects as reported in our previous work, to remove Sn⁴⁺ from the precursor, combined with a PbF₂ post-treatment to passivate surface defects,” he went on to say.

The Sn-Pb test cells measured 0.09 cm2. The basic stack was as follows: indium tin oxide (ITO) substrate, P3CT-Cs layer, perovskite, lead fluoride, electron transport layer (ETL) based on buckminster fullerene (C60), bathocuproine (BCP) and insulating lithium fluoride (LiF), and copper (Cu) contacts.

The strategy enabled the efficiency of the SnF₂-free tin lead perovskite solar cell to reach 24.07% compared to 16.43% of the control device. As for photothermal stability, the cells without the SnF₂ additive retained 60% of their initial efficiency after continuous operation at 85 C under maximum power point (MPP) conditions for 550 h.

The negative effect of SnF₂e was evident in testing. For example, the researchers noted that both Cu and ITO electrodes had reactions “even at room temperature or without light soaking,” indicating the “corrodibility of migrated ion and reaction products.”

The fabrication requires precision but the process is straightforward, according to the scientists. “Tin-containing perovskites require a carefully controlled atmosphere with extremely low oxygen levels, and the film-forming temperature along with associated processing parameters must be finely tuned while using high-purity SnI₂. Even so, device fabrication remains straightforward,” said Zhang.

The scientists concluded that the work has implications for overcoming the stability bottlenecks of Sn-Pb single-junction and all-perovskite tandem solar cells. Their work is described in “A tin fluoride-free, efficient and durable tin-lead perovskite solar cell,” published by nature communications.

“We are working on the simultaneous efficiency and stability improvements of all-perovskite tandem solar cells and tin-lead perovskite solar cells,” said Zhang, referring to the future direction of the team's work.