By Sekhar Tatineni, Vice President of Technology, ES Foundry
At CLEANPOWER 2026, I discussed one of the most important technology questions facing U.S. solar manufacturing: Which solar cell technologies can help the United States build a stronger, more resilient manufacturing base?
The conversation around domestic solar manufacturing often focuses on capacity, supply chain security, domestic content, FEOC risk and project finance. All of those issues matter. But behind them is a more technical question with real commercial consequences. PERC, TOPCon, HJT and back-contact cells all have a place in the solar roadmap, but each brings different strengths, risks and manufacturing realities. The challenge is identifying which technologies can be produced reliably, scaled responsibly and supported by a supply chain that gives customers confidence.
Watch my full CLEANPOWER 2026 presentation, “How PERC, TOPCon, HJT and Back-Contact Will Shape Domestic Manufacturing,” here.
The technology roadmap is not just about efficiency
Solar cell technology is often discussed as a race toward higher efficiency. In that context, newer n-type technologies such as TOPCon, HJT and back-contact designs understandably get a lot of attention.
TOPCon offers higher efficiency potential and has become mainstream globally. HJT provides strong long-term performance potential with low degradation characteristics. Back-contact technologies can deliver maximum power potential by moving contacts to the rear of the cell, improving aesthetics and design flexibility.
But efficiency is only one part of the equation.
For a technology to support domestic manufacturing at scale, it also needs proven production processes, available equipment, trained operators, reliable materials, strong yield performance and a clear path to bankability without IP challenges. It must be manufacturable in real factory conditions.
That is crucial because the United States is still rebuilding its solar cell manufacturing base. The country has strengths in innovation, capital and market demand, but there are still meaningful gaps in high-volume manufacturing experience, workforce depth, process know-how, equipment availability and domestic materials supply. Those gaps make it difficult to jump directly into the most advanced technologies at scale without adding cost, complexity and execution risk.
The path forward has to balance ambition with manufacturing reality.
TOPCon brings efficiency promise — and IP complexity
TOPCon has become one of the most closely watched solar cell technologies because it offers a meaningful efficiency step beyond PERC while building on some existing manufacturing concepts. It is increasingly viewed as a mainstream next-generation architecture.
TOPCon also introduces a more complicated intellectual property landscape. Much of the IP risk around TOPCon is concentrated in areas such as tunnel oxide formation, polysilicon passivation and laser-contact opening. For manufacturers in the United States and Europe, that creates important questions around freedom to operate, market access and long-term technology strategy.
That does not mean TOPCon will not play an important role domestically, but it does mean that manufacturers and customers need to evaluate more than performance claims. They need to understand the IP position, supply-chain implications and commercial risk that may come with the technology path.
For domestic manufacturing, this is especially important. The U.S. solar industry is trying to build capacity that is financeable, defensible and durable.
HJT has strong long-term potential, but the materials ecosystem is still developing
Heterojunction technology, or HJT, is another promising advanced cell architecture. It offers ultra-high efficiency potential, very low process temperatures and attractive degradation characteristics. It is a strong long-term technology candidate.
But HJT also depends on specialized materials and processes that are not yet fully supported by the U.S. supply chain.
One example is the TCO, or transparent conductive oxide, supply chain. HJT cells use TCO layers on both sides of the cell. The targets used to deposit those layers eventually become depleted and often require return, recycling and replacement. Today, the domestic ecosystem for TCO materials, recycling and reverse logistics is still limited.
That creates a practical challenge. Even if the cell technology is strong, the supporting supply chain must be ready to support volume production. Supplier localization, recycling capacity and materials availability will need to mature before HJT can be fully scaled in a resilient U.S. manufacturing environment.
Again, the issue is not whether HJT has a future: It’s timing, infrastructure and ecosystem readiness.
Back-contact technology points to the future, but depends on manufacturing maturity
Back-contact cells offer another important pathway. By moving all contacts to the rear of the cell, these technologies can increase usable front-side area, improve module appearance and support high-efficiency products.
But back-contact manufacturing can also be more complex. It depends heavily on architecture, process integration, passivation stacks, vias or through-cell structures, and advanced interconnection approaches. That makes the technology powerful but complicated. It is more dependent on mature manufacturing capabilities and a well-developed supplier base than other technologies.
For the U.S. market, back-contact may be part of the longer-term roadmap. But like TOPCon and HJT, it must be evaluated through the lens of manufacturability, cost, IP position and supply-chain support.
Why PERC remains highly relevant to the United States
Against that backdrop, PERC remains the most practical and important technologies for U.S. solar cell manufacturing today.
PERC is mature, proven and widely understood. It has more than a decade of field performance data and billions of modules deployed globally. Its reliability is supported by extensive industry experience, independent testing and long-term performance analysis. For developers, lenders and investors, it’s a track record on which they can depend.
PERC also offers a more straightforward manufacturing path. The process flow is well established, the equipment ecosystem is mature, and the workforce training requirements are more manageable than with some newer cell architectures. That can support faster factory ramp-up, higher process consistency and reduced execution risk.
From an economic standpoint, PERC can offer lower capital intensity than more complex advanced technologies. Simpler equipment and proven process flows can reduce upfront investment, shorten learning curves and support faster returns on investment.
PERC also carries a cleaner IP profile compared with some newer technologies. That is important to U.S. manufacturers seeking to reduce dependence on restricted materials, proprietary, foreign-controlled technologies and uncertain freedom-to-operate positions.
Most importantly, PERC has a domestic manufacturing foundation. It allows the United States to build real cell production capability now while strengthening the people, processes, suppliers and operating discipline needed to support future technology transitions.
The U.S. needs a phased approach, not a shortcut
The goal should be to build a domestic solar manufacturing ecosystem that can scale today and evolve tomorrow. That requires a phased approach.
First, the United States needs to build manufacturing excellence: strong process control, reliable quality systems, trained operators and repeatable production. Second, it needs to strengthen the domestic supply ecosystem by expanding reliable sources for materials, components, consumables and equipment support. Third, it needs to build technical workforce depth and process know-how. From there, the industry will be better positioned to transition into advanced cell technologies at scale.
Skipping those steps could create factories that look good in announcements but struggle in execution.
Developers, EPCs, module manufacturers and asset owners are paying attention. Project decisions, domestic content strategies and supply-chain diligence is happening now. Customers need technology that is advanced, available, reliable, documented and bankable.
ES Foundry’s role in the roadmap
At ES Foundry, we are focused on manufacturing U.S.-made solar cells that can support today’s market needs while helping build the foundation for tomorrow’s technology evolution.
PERC offers a proven, scalable and bankable pathway for domestic cell production. It supports lower manufacturing risk, stronger supply-chain resilience and greater confidence for customers working through procurement, finance and compliance decisions. It also creates the operational base needed to participate in the next generation of solar cell manufacturing as the U.S. ecosystem matures.
TOPCon, HJT and back-contact technologies will continue to shape the future of solar. Each brings important strengths. But the future of U.S. solar manufacturing will be built on the ability to scale high-quality production, reduce risk, support bankability and strengthen the domestic supply chain.
PERC provides that practical starting point.
The strongest path forward is not about choosing between today and tomorrow. It is about building the manufacturing platform that allows the U.S. solar industry to deliver today and evolve with confidence.
To hear the full CLEANPOWER 2026 discussion, including my breakdown of PERC, TOPCon, HJT and back-contact technologies, watch the full presentation here.