NexWafe boost for solar wafers
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NexWafe in Germany has shown efficiency of 24.4% for its solar wafers made on a commercial production line.
The move is a significant breakthrough in its solar wafer manufacturing technology with cell efficiencies equivalent to traditional Czochralski (CZ) wafers in a production environment. The company has also shown advancements in ultra-thin wafers for space applications, as well as data on next-generation tandem-junction cells for its EpiNex technology.
The NexWafe EpiNex solar wafers achieved 24.4% efficiency on a commercial M6 heterojunction (HJT) cell line, for the first time delivering performance parity with conventional CZ wafers. Modules made from both TopCon and HJT solar cells match or exceed the performance of CZ wafers.
This data validates NexWafe’s direct gas-to-wafer process as a drop-in replacement for conventional CZ wafers, while offering the potential for significant cost savings by reducing material waste, lowering energy consumption by 40% and eliminating the saw damage etch process step in cell production.
Vonventional CZ technology results in 50% material waste due to polysilicon losses, but EpiNex reduces this waste to under 10%, primarily by eliminating wire saw kerf losses.
Applications in space require thinner wafers with enhanced thermal stability, precise flatness and superior material quality. The oxygen content of EpiNex wafers is 20 times lower than conventional CZ wafers, enabling thermal stability and helps improve cell performance under high-temperature conditions.
NexWafe used EpiNex wafers to develop ultra-thin 70μm cells to address the growing demand for solar cells to power low earth orbit satellites. These cells exhibit radiation performance comparable to conventional CZ PERC and provide a significant power-to-weight ratio advantage, making them ideal for space applications.
NexWafe also made significant strides in next-generation cell applications. In collaboration with Swiss research group CSEM, tandem perovskite 2-junction cells using NexWafe’s EpiNex wafers achieved 28.9% efficiency, demonstrating their potential for advanced solar technologies. With superior smoothness at nano-scale, EpiNex wafers provide a suitable platform for low-cost, solution-processed tandem perovskite cells.
This is key to reshoring manufacturing, says NexWafe. By reducing material waste and energy consumption, NexWafe shifts wafer manufacturing onto a new cost curve, along with higher performance.
“These latest results are transformative for photovoltaic wafer manufacturing. EpiNex has the potential to shake up the solar industry in a way similar to the historic shift from polycrystalline ingots to single-crystal silicon. Just as that transition led the entire industry to retool its processes, unlocking significant efficiency gains and paving the way for today’s high-performance solar technology, EpiNex will drive a similar transformation,” said Davor Sutija, CEO of NexWafe. “Our technology creates an opportunity for regionally based manufacturers to compete with China, enabling a leapfrog in performance and cost, while significantly reducing carbon footprint.”
NexWafe plans to launch its next generation tool, the ProCon 2.5, by June 2025. This uses an enhanced heating systems and inline atmospheric pressure chemical vapour deposition to deposit monocrystalline silicon over an area of 1.3m x 50cm, equivalent to over fourteen G12 wafers in a single pass.
This is the largest area ever achieved for epitaxial silicon deposition with deposition rates of 5μm per minute and temperature uniformity achieving a total thickness variation (TTV) below 40%.
NexWafe has secured conditional purchase orders for gigawatt-scale production, targeting both conventional utility-scale and space markets in India, North America and Europe.
“We’re seeing tremendous interest from solar cell manufacturers, especially in the U.S. and India, seeking a domestic supply of wafers. We’ve secured over 5GW in conditional supply agreements for mainstream solar markets and 250MW for ultra-thin cells for specialist applications, including space,” said Jonathan Pickering, NexWafe’s Vice President of Business Development in the U.S.
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