Amid intense competition and rapid technological evolution, the PV industry stands at a critical juncture. TOPCon, heterojunction (HJT), and back-contact (BC) technologies are all vying for dominance. DAS Solar CTO Dr. Dengyuan Song offers his insights as to why TOPCon will remain the industry’s leading technology over the next 3-5 years.
Song emphasizes three critical factors for determining the PV industry’s mainstream technology: LCOE, cell efficiency and industrial ecosystem.
“The ecosystem is paramount,” Song explains. “It determines the speed of cost reduction, as energy products must be economically viable to replace traditional energy sources.” While critical, efficiency serves as a means to reduce costs rather than an end goal. Song notes that, even though gallium arsenide (GaAs) cells boast efficiencies nearing 50%, their high cost makes them unsuitable for terrestrial applications. In addition, low LCOE is also essential for large-scale replacement of fossil fuels, solidifying the pathway for renewable energy adoption.
TOPCon technology has rapidly gained market share, climbing from 23% in 2023 to an estimated 75% in 2024, with projections exceeding 80% in 2025 according to China’s Photovoltaic Industry Development Roadmap. This rise can be attributed to the technology’s structural advantages, particularly its advanced passivation technology, which significantly enhances efficiency while reducing costs.
“Solar cell efficiency and cost depend heavily on the passivation structure,” Song explains. “TOPCon’s comprehensive passivation enables full-area optimization, overcoming the limitations of the partial passivation seen in PERC cells.” By comparison, BC technology primarily focuses on electrode configurations, making its performance contingent on the underlying passivation method, whether TOPCon or HJT.
Song has studied historical trends and concluded that each cell technology follows a 10-year life cycle, resembling a bell curve. This trajectory starts with a market share of 20%, peaks at 70-80%, and then tapers to around 10% over the following five years.
Based on this model, Song predicts that TOPCon will dominate the market for the next 3-5 years, driven by its unparalleled passivation capabilities, high efficiency and scalability. “Crystalline silicon’s high stability, non-toxic nature and abundant resources ensure it will remain the dominant platform for at least the next decade,” Song adds.
TOPCon technology currently achieves a laboratory efficiency record of 27.3%, with its theoretical limit at 29.4%. To validate the potential of TOPCon, Song has analyzed the theoretical and laboratory efficiencies of 26 different cell types. His findings reveal that crystalline silicon cells are by far the closest to their theoretical efficiency, with a mere 2.11% gap.
Song outlines clear steps for further improvement, emphasizing the importance of minimizing surface recombination and enhancing carrier lifetimes. A simulation by UNSW’s Professor Martin Green identified two key factors for increasing efficiency to 28%. Firstly, carrier lifetimes should exceed 4.5 ms. and, in the meantime, surface recombination currents should be below 5.6 fA/cm².
In fact, the carrier lifetime in current silicon materials can fully meet these requirements, especially with full-area contact passivation. However, achieving a recombination current of 5.6 fA remains very challenging. The best current level is approximately 8 fA. Therefore, to continue improving efficiency, surface recombination becomes the most critical factor.
Song expressed confidence that these milestones are achievable, paving the way for continued efficiency improvements in the future.
Looking ahead, DAS Solar aims to surpass 40% cell efficiency by leveraging its robust technology strength and fostering advancements across multiple technologies. “With TOPCon technology as the core, we are committed to pushing the boundaries of PV technology, achieving new levels of efficiency, and driving the global energy transition,” Song concludes.
