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Edited by Justin Brown
As solar makers squeeze costs, a radical alternative to silver solder could rewire the entire industry.
The photovoltaic industry consumed 186.6 million ounces of silver in 2025 — a 6% decline from 197.5 Moz the year before — according to the World Silver Survey 2026, compiled by Metals Focus for the Silver Institute and reported by PV Magazine. In the same period, researchers at Forschungszentrum Jülich were presenting a rather different response to the same cost pressure: a solderless nickel anisotropic conductive tape, roughly 10 µm thick, used to interconnect solar cells at room temperature. In their test modules, the assembly came through 200 thermal cycles down to −40 °C with less than 1% power loss, according to work shown at the Metallization and Interconnection Workshop in Berlin on October 20–21, 2025.
Those two numbers sit at opposite ends of the same problem. One is a market-level accounting of how much silver the module industry still buys every year. The other is a laboratory attempt to change the physics of how a cell gets wired at all — and, by extension, how much metal and how much heat that step demands.
The World Silver Survey’s headline for PV is a contraction, not a collapse. Silver demand from the solar sector fell to 186.6 Moz in 2025 from 197.5 Moz in 2024, and Metals Focus expects a considerably steeper drop ahead: the survey forecasts a further decline of around 19% in 2026, to roughly 151 Moz, per PV Magazine’s reporting of the figures.
The pressure behind that trajectory is not subtle. Silver averaged just over $40 an ounce across 2025 — up around 42% year over year, according to the same survey — while total industrial offtake slipped 3% to 657.4 Moz and the market logged its fifth consecutive annual deficit, at 40.3 Moz. When a critical metallization input reprices that hard, cell makers respond the way they have responded for a decade: thrifting. Finer fingers, narrower busbars, thinner screen-printed pastes, and, increasingly, substitution work aimed at copper or at contact schemes that use less silver per watt in the first place.
The survey frames thrifting and alternative metallization as the industry’s cost-pressure response rather than as a solved problem, and that distinction matters. A 6% decline in ounces does not tell you whether the industry has structurally weaned itself off silver or whether it has simply shipped modules with less paste on them while volumes grew. It does tell you that the material is now a line item that R&D groups across Europe are designing around — including at the interconnection step, which has historically been treated as a solder-and-ribbon commodity operation rather than a materials question.
Conventional stringing joins cells with soldered copper ribbon. That works because crystalline silicon tolerates the localized thermal excursion. It works considerably less well for the cell architectures that the industry is now pushing toward efficiency records.
Silicon heterojunction cells carry thin passivating layers and transparent conductive oxides that degrade under soldering temperatures. Perovskite-silicon tandems are worse: the perovskite absorber itself is thermally sensitive, and the thermal budget of any downstream process step becomes a design constraint on the entire module. That is the motivation stated in the Jülich contribution to MIW 2025, presented by Benedikt Fischer and Yanxin Liu under the title “Room-Temperature Interconnection of Thermally Sensitive Solar Cells Using Electrically Conductive Tape.” If the cell cannot be heated, the interconnect has to be made cold.
An anisotropic conductive tape is a way of doing that. The adhesive conducts in one direction — through its thickness, cell to ribbon — while remaining insulating in the plane, so that particles bridging the joint do not short adjacent contacts. In the Jülich work, the conductive pathway is nickel rather than silver-coated filler, in a film on the order of 10 µm thick, applied and cured without a solder reflow step. The cell is never taken up to soldering temperature.
The materials logic runs in two directions at once. It removes the thermal insult that keeps heterojunction and tandem architectures from being interconnected with standard equipment, and it puts a base metal where the industry has conventionally used silver-bearing or solder-based joining chemistry.
Here the caveats need to be as precise as the numbers. The result reported at MIW 2025 is a test module in a laboratory research line — single-cell scale, not a certified commercial panel, and not a product with a name, a datasheet, or a supply agreement. Less than 1% power loss after 200 thermal cycles to −40 °C is a meaningful early durability signal for a room-temperature joint, because thermal cycling is precisely where a cold-formed adhesive interconnect would be expected to fail: differential expansion between cell, adhesive, and ribbon working the contact loose over repeated excursions. The joint held.
What it does not establish is field lifetime. Standard module qualification runs cycling in combination with damp heat, humidity-freeze, mechanical load, and UV exposure, on full-format laminates, over durations that a workshop presentation does not cover. Nor does the Jülich work claim otherwise.
There is also a mechanical trade-off flagged in the research line itself: the thin nickel tape shows weaker peel and adhesion performance than the thicker alternatives tested alongside it. That is a soft caveat, not a disqualifier — but it is the sort of finding that determines whether a 10 µm film survives lamination, handling, and two decades on a roof, or whether the recipe needs more thickness and therefore more material.
And nothing in the tape work substitutes for the industry-wide thrifting the World Silver Survey is measuring. The 186.6 Moz consumed in 2025, and the roughly 151 Moz Metals Focus projects for 2026, are being driven down by front-side metallization changes at cell level, not by interconnection adhesives in a German research institute. What Jülich has is an early, lab-scale demonstration that a base-metal, room-temperature joint can survive 200 cycles to −40 °C with less than 1% loss — one line of attack on a materials bill the survey shows is still very much unresolved.
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