A series of recent laboratory breakthroughs in solvent-free perovskite solar cell fabrication have pushed efficiencies past 24% on small devices and demonstrated, for the first time, fully roll-to-roll printed modules built under normal room conditions. These results, spread across multiple peer-reviewed studies, suggest that eliminating toxic solvents from the manufacturing process could dramatically reduce the capital and environmental costs of scaling perovskite photovoltaics. The question now is whether these lab-scale wins can translate into durable, factory-ready products before the technology’s well-known stability problems catch up with it.
Vacuum Deposition Pushes Small-Cell Efficiency Past 24%
The strongest efficiency numbers for solvent-free perovskite cells come from sequential vacuum evaporation, a technique that layers precursor materials in a controlled chamber without any liquid solvents. A study in Science Advances reported a power conversion efficiency (PCE) of 24.42% on a 0.1 cm² cell, 23.44% on a 1.0 cm² cell (with a certified 22.6%), and 19.87% on a 14.4 cm² aperture-area mini-module. Those mini-module numbers matter because efficiency typically drops sharply when devices get larger, and holding close to 20% at that scale signals real manufacturing potential. The same devices showed storage stability exceeding 4,000 hours in dry air, a promising shelf-life indicator even if it falls short of the decades-long outdoor durability that commercial panels require.
A separate approach, detailed in a Nature Materials report, used an all-vacuum-deposited method targeting wide-bandgap perovskite compositions, which are especially valuable for tandem cells stacked on top of silicon. That study achieved a lab efficiency of 19.3% and a certified 18.35% on a 0.25 cm² cell, along with operational stability to 1,080 hours under the ISOS-L-2 testing protocol, a standardized light-soaking stress test. Wide-bandgap cells typically trail their narrower-bandgap counterparts in raw efficiency, so these figures represent strong performance for the category. Taken together, the two studies show that vacuum-based, solvent-free routes can compete across different perovskite compositions and device sizes, while still edging into the same efficiency territory that leading crystalline technologies occupy.
Roll-to-Roll Printing Moves Beyond the Lab Bench
High efficiency on a tiny chip means little if the manufacturing method cannot scale. That is where roll-to-roll (R2R) printing enters the picture, and two recent studies have extended the solvent-free concept from the absorber layer to the electrodes and full module assembly. Research described in Advanced Energy Materials demonstrated a vacuum-free, solvent-free method for depositing printed electrodes on flexible substrates, eliminating a long-standing problem: solvent migration from wet electrode inks into the sensitive perovskite layer beneath. By removing both vacuum steps and solvent exposure, this approach simplifies the equipment needed and reduces contamination risk during high-speed fabrication, while also opening the door to lightweight, flexible products that silicon cannot easily match.
Building on that foundation, a team reported in Nature Communications the first demonstration of entirely roll-to-roll fabricated perovskite solar cell modules under ambient room conditions. Instead of vacuum-deposited metal electrodes, which add cost and complexity, these modules used printed carbon electrodes. Carbon is cheap, abundant, and chemically stable, which makes it an attractive replacement for silver or aluminum back contacts. The fact that every layer, including the electrodes, was printed in open air rather than inside a vacuum chamber represents a significant step toward the kind of continuous, high-throughput manufacturing lines already common in packaging and flexible electronics, suggesting that perovskites could eventually be produced on equipment similar to that used for newspapers or polymer films.
The Cost Advantage Over Silicon
Silicon solar cells dominate the global market, and their per-watt costs have fallen steeply over the past decade. But the factories that produce them require enormous upfront investment in high-temperature furnaces, clean rooms, and ingot-pulling equipment. As researchers at the University of Cambridge have noted, silicon modules are inexpensive only after that capital has been sunk, whereas perovskite devices can be made using lower-temperature, potentially simpler tools. Solvent-free vacuum and printing methods sharpen that advantage further by cutting out the need for expensive solvent handling, fume extraction, and hazardous waste disposal systems that solution-based perovskite lines would still require, reducing both regulatory burden and ongoing operational costs.
There is a counterpoint worth weighing, however. Vapour deposition of perovskite materials, while it sidesteps solvent toxicity, introduces its own expense. As the University of Oxford flagged years ago, vapour deposition “overcomes a problem but comes at additional costs,” primarily because vacuum chambers are energy-intensive to operate and maintain. The roll-to-roll printing route avoids that trade-off entirely by working at atmospheric pressure, but it has not yet matched the efficiency records set by vacuum methods. Public efficiency tables maintained by the U.S. National Renewable Energy Laboratory still show the very highest perovskite and tandem performances coming from meticulously optimized, small-area devices, underscoring that low-cost manufacturing concepts must eventually converge with record-setting device physics to be competitive at scale.
Stability Remains the Hardest Unsolved Problem
Efficiency records grab headlines, but long-term stability will ultimately determine whether solvent-free perovskite technologies can displace or complement silicon in mainstream markets. A comprehensive review of commercialisation pathways hosted on PubMed Central notes that companies pursuing perovskite photovoltaics are already wrestling with encapsulation, module design, and reliability standards that go far beyond the 1,000–4,000 hour stability tests reported in most academic papers. Even when absorber layers are fabricated without solvents, they remain vulnerable to moisture, oxygen, heat, and ultraviolet light, all of which can trigger complex degradation pathways that are not yet fully understood. This gap between laboratory testing and real-world exposure conditions is one of the main reasons investors and bankability experts still treat perovskite projects cautiously.
Material degradation is not just a matter of cosmetic discoloration or minor efficiency loss; it can fundamentally limit device lifetimes. Another review available through PubMed Central highlights how the perovskite layer can decompose under high temperatures and sustained illumination, releasing volatile species and halides that interact with adjacent transport layers and electrodes. Those processes may be accelerated or altered when devices are built on flexible substrates or paired with carbon contacts, as in the solvent-free, roll-to-roll concepts now emerging. For solvent-free manufacturing to fulfill its promise, researchers will need to couple these process innovations with robust encapsulation, carefully engineered interfaces, and standardized testing that better mimics decades of outdoor operation rather than months of controlled laboratory stress.
From Lab Breakthroughs to Bankable Products
Taken together, the recent advances in vacuum deposition and roll-to-roll printing show that solvent-free perovskite solar cells are no longer a speculative idea confined to theory and proof-of-concept devices. High-efficiency, small-area cells exceeding 24% demonstrate that removing liquid solvents does not inherently cap performance, while the first fully printed, ambient-condition modules prove that every layer of a perovskite stack can be deposited using scalable techniques. These achievements chip away at two of the biggest perceived barriers to commercialisation: manufacturing complexity and environmental impact. They also align with the interests of companies already moving pilot-scale production forward, which must navigate intellectual property, supply chains, and certification frameworks alongside the core science.
Yet the path from laboratory breakthrough to bankable product is rarely straightforward, and perovskite photovoltaics are no exception. The field now faces a three-way optimization problem: maintain record-level efficiencies, exploit the cost and flexibility advantages of solvent-free manufacturing, and deliver stability that satisfies conservative utility and rooftop investors. Solvent-free processes will likely play a central role in that equation because they simplify permitting, reduce worker exposure, and make it easier to site factories in regions with strict environmental rules. Whether vacuum-based routes, roll-to-roll printing, or some hybrid approach ultimately dominates may depend less on who wins the next efficiency record and more on who can demonstrate, with independently verified data, that their modules will reliably generate clean electricity for decades at a price that undercuts both silicon and emerging competitors.
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*This article was researched with the help of AI, with human editors creating the final content.
