The solar sector's appetite for silver is shrinking, but the hunt for cheaper interconnection methods is accelerating. According to the World Silver Survey 2026, prepared by Metals Focus for the Silver Institute and cited by PV Magazine, the photovoltaic industry bought 186.6 million ounces of silver in 2025—a 6% reduction from 197.5 million ounces in 2024. At the same time, researchers at Forschungszentrum Jülich unveiled a solderless nickel anisotropic conductive tape, measuring roughly 10 µm thick, designed to join solar cells at room temperature. When tested in their prototype modules, the assembly withstood 200 thermal cycles down to −40 °C while maintaining less than 1% power loss, as demonstrated at the Metallization and Interconnection Workshop in Berlin on October 20–21, 2025.

These two developments address the same underlying challenge from opposite directions. One captures the scale of silver consumption across the module manufacturing sector each year. The other represents a laboratory effort to fundamentally alter how cells are wired together—and thereby reduce the quantity of metal and thermal stress required in that step.

Silver demand continues its downward slide

The World Silver Survey documents a contraction rather than a collapse in the photovoltaic sector. Consumption fell to 186.6 million ounces in 2025 from 197.5 million ounces in 2024, and Metals Focus forecasts a much steeper decline ahead: the survey projects a drop of roughly 19% in 2026, reaching approximately 151 million ounces, according to PV Magazine's reporting.

The forces driving this trajectory are substantial. Silver averaged just over $40 per ounce during 2025—a 42% increase year over year per the same survey—while overall industrial demand slipped 3% to 657.4 million ounces and the market recorded its fifth straight annual deficit of 40.3 million ounces. When a key metallization input experiences such a sharp repricing, cell manufacturers respond through cost reduction strategies refined over the past decade: narrower busbars, finer fingers, thinner screen-printed pastes, and increasingly, substitution approaches that rely on copper or contact designs requiring less silver per watt.

The survey treats thrifting and alternative metallization as an ongoing industry response rather than a finished solution, a distinction with real implications. A 6% decline in ounces does not reveal whether manufacturers have fundamentally reduced their silver dependence or simply applied thinner paste coatings while production volumes expanded. What it does show is that silver has become a design consideration for R&D teams across Europe—including at the interconnection stage, traditionally managed as a straightforward solder-and-ribbon commodity operation rather than a materials engineering problem.

Why advanced cell types demand room-temperature assembly

Traditional cell stringing employs soldered copper ribbon, a method that functions adequately with crystalline silicon's thermal tolerance. The approach encounters serious difficulties with the cell architectures now driving efficiency improvements.

Silicon heterojunction cells feature delicate passivating layers and transparent conductive oxides that deteriorate when exposed to soldering heat. Perovskite-silicon tandem cells present an even greater challenge: the perovskite absorber itself is thermally fragile, making the thermal budget of every subsequent process step a critical constraint on module design. This concern motivated the Jülich presentation at MIW 2025, delivered by Benedikt Fischer and Yanxin Liu under the title "Room-Temperature Interconnection of Thermally Sensitive Solar Cells Using Electrically Conductive Tape." When cells cannot withstand heating, the interconnection method must operate at ambient temperature.

An anisotropic conductive tape provides one solution. The adhesive conducts through its thickness—from cell to ribbon—while remaining non-conductive across its plane, preventing conductive particles from creating short circuits between adjacent contacts. In the Jülich approach, nickel forms the conductive pathway rather than silver-coated fillers, embedded in a film approximately 10 µm thick, applied and cured without a solder reflow step. The cell never reaches soldering temperature.

The materials strategy operates on two fronts simultaneously. It eliminates the thermal damage that prevents heterojunction and tandem architectures from using conventional interconnection equipment, and it replaces silver-bearing or solder-based joining chemistry with a base metal.

What the durability test reveals—and what it does not

Precision matters when interpreting the MIW 2025 results. The work presented represents a test module within a laboratory research program—single-cell scale rather than a certified commercial product, with no product name, datasheet, or supply chain in place. The less than 1% power loss after 200 thermal cycles to −40 °C constitutes a meaningful early durability indicator for a room-temperature joint, since thermal cycling is exactly where a cold-formed adhesive interconnect would be expected to fail: differential expansion between cell, adhesive, and ribbon stresses the contact through repeated temperature swings. The joint survived.

What the test does not demonstrate is field longevity. Standard module qualification combines thermal cycling with damp heat exposure, humidity-freeze cycles, mechanical loading, and UV exposure, applied to full-size laminates over timescales that a workshop presentation cannot address. The Jülich team makes no such claims.

The research also identifies a mechanical limitation: the thin nickel tape exhibits weaker peel and adhesion performance compared to thicker variants tested in parallel. This represents a soft constraint rather than a fundamental obstacle—but it is precisely the kind of finding that determines whether a 10 µm film survives lamination, handling, and two decades of outdoor exposure, or whether the formulation requires greater thickness and therefore additional material.

Importantly, the tape development does not replace the industry-wide cost reduction the World Silver Survey documents. The 186.6 million ounces consumed in 2025 and the roughly 151 million ounces Metals Focus projects for 2026 are being reduced through front-side metallization improvements at the cell level, not through interconnection adhesives in a German laboratory. What Jülich has demonstrated is an early, lab-scale proof that a base-metal, room-temperature joint can endure 200 cycles to −40 °C with less than 1% loss—one approach among several to addressing a materials cost structure the survey shows remains substantially unresolved.

Source: Silicon Canals