HJT Remains Strong On Technology But Faces Market Challenges

Heterojunction (HJT) solar technology continues to demonstrate strong technical fundamentals. However, its market position has become more uncertain under current industry conditions.

Speaking at the TaiyangNews High-Efficiency Solar Technologies Conference 2025, Kaining Ding, Head of PV-ThynC Lab at Forschungszentrum Jülich, presented a balanced view of HJT’s status and outlook. He compared the positive and negative arguments around the technology, noting that current perceptions are strongly influenced by market conditions rather than by the technology itself.

HJT remains a strong device architecture, largely due to its excellent surface passivation, which enables high bifaciality and a low temperature coefficient. These features support strong module performance and have long positioned the technology as a premium option.

However, the efficiency improvements in TOPCon, supported by processes such as LECO, have narrowed the performance gap with HJT. As a result, the efficiency premium is no longer sufficient to justify a higher selling price.

Several developments could influence HJT’s competitiveness going forward. One key area is copper metallization, which could reduce or eliminate the use of silver. HJT has already significantly reduced silver consumption, and further reductions could improve cost structures.

Another potential development highlighted during the presentation is Hot-wire CVD (HWCVD). It enables double-sided wafer processing and higher throughput, which could reduce CapEx. That said, commercialization remains limited due to insufficient industry engagement and throughput challenges. Some pilot lines exist, and attempts have been made to scale to GW-level production, but these are not currently operating under present market conditions.

Hybrid architectures are also emerging, with back-contact (BC) designs incorporating HJT processes that are now under active exploration. Existing HJT equipment can be adapted for these structures, and pilot production is already underway. HJT also continues to play an important role in tandem technologies. Currently, the highest efficiencies in perovskite-silicon tandem cells are achieved using HJT as the bottom cell, although TOPCon could also be used in the future, he added.

Further design innovations are being explored, including the use of one-third-cut wafer formats, where wafers are processed in smaller sizes from the outset. This approach has shown potential for higher module power in R&D. At the same time, zero-busbar (0BB) concepts continue to evolve, with increasing interest in integrated film-based designs.

Cost dynamics for HJT have improved in recent years. According to Ding, the production cost difference with TOPCon has reduced to around 0.05 RMB/Wp, although HJT remains slightly more expensive. However, higher CapEx remains a key challenge. Under current market conditions, with many production lines operating below full utilization, depreciation costs per watt increase, putting additional pressure on HJT. At the same time, ongoing price pressure and overcapacity are affecting all technologies, but the impact on HJT is more pronounced.

The industry’s structure also plays an important role in shaping HJT’s development. In China, deployment is largely driven by newer entrants rather than established Tier-1 manufacturers, with companies such as Huasun leading capacity expansion. State-owned entities, including SPIC and CNBM, are also present, although with relatively smaller capacities, while among established players, Risen remains one of the few with notable involvement. At the same time, major manufacturers such as LONGi, Tongwei, and Trina continue to operate HJT pilot lines.

Ding also pointed to the importance of the value chain feedback loop. Investments in large-scale capacity tend to attract supplier interest, which in turn supports improvements in materials and equipment. Over time, this helps reduce costs and strengthen overall competitiveness, creating the conditions for further expansion.

HJT has already reached around 40 GW of production capacity, indicating that this loop has been initiated. However, current market conditions, particularly price dumping, have disrupted this cycle. If the downturn persists, the value chain could weaken further. Despite current challenges, some developments point to potential opportunities, including expansion into the US market.

The US market could play a particularly important role. TOPCon faces patent-related challenges in this region, creating space for alternative technologies such as HJT. At the same time, most US manufacturing capacity is based on PERC, creating room for higher-efficiency technologies to gain traction. There are also indications of potential future expansion, although these remain unconfirmed.

From a broader perspective, PV technology transitions have historically been driven by efficiency rather than cost alone. Technologies such as aluminum BSF and multicrystalline silicon lost relevance when they could no longer compete on efficiency.

In the current landscape, the efficiency gap between TOPCon, BC, and HJT remains relatively small. HJT must compete with BC on efficiency and with TOPCon on cost, and whether it can outperform either remains uncertain. HJT also offers secondary advantages, including high bifaciality, which can support lower LCOE, and suitability for specific applications such as vertical installations. Rising silver prices could favor HJT, which uses less silver than TOPCon, narrowing the module cost gap.

Recent industry discussions suggest that HJT continues to remain under consideration, with some pointing to markets such as the US as potential drivers in sustaining the value chain through the current downturn.

To access the full presentation video titled Status & Outlook of HJT, click here.