As market shares shift among cell technologies, upstream advancements are setting the stage for broader performance gains across all architectures. LONGi’s TaiRay wafer, introduced last year, earns a mention here. The key aspect of this wafer, according to LONGi, is advancement in silicon wafer technology, aligning closely with the evolving needs of high-efficiency solar cell manufacturing, underscoring that wafer and cell development are inseparably linked. This new ingot growing technology results in wafers that address performance and cost challenges. Traditionally, ingot production evolved from the standard Czochralski (CZ) process to Recharge Czochralski (RCZ) to Continuous Czochralski (CCZ) methods, each aiming to optimize cost, resistivity control, and material purity. However, challenges remained, particularly with CCZ, where increased oxygen content and metal impurity accumulation lead to compromised lifetime and process yields, especially in n-type wafers (see Next-Gen Solar Cell Technologies & Projections).
To address this issue, LONGi developed a new pulling approach: the Trailblazing Recharge Czochralski (TRCZ) technology. TRCZ preserves the productivity and cost advantages of RCZ while considerably improving resistivity uniformity and wafer quality across the ingot. This innovation led to the introduction of the TaiRay wafer, which has been available commercially since late 2024. This wafer offers several breakthroughs. It achieves exceptional consistency in bulk resistivity from the seed to the tail ends of the ingot, maintaining variation within a tight 1.1–1.2 ratio. This uniformity ensures that module production achieves higher efficiency yields, improved EL uniformity, and better reliability. Moreover, TaiRay wafers are compatible with all mainstream cell technologies, including TOPCon, HJT, and BC architectures. The wafers are offered in different geometries and thicknesses, meeting the demands of various cell vendors.
One of the standout features of the TaiRay wafer is its optimized dopant engineering. By using antimony, LONGi has reduced the migration activation energy of intrinsic metal impurities, making them easier to remove during the gettering process. This advantage is especially critical for sensitive technologies like HJT. Tests demonstrated that even tail-end wafers maintain high performance after gettering, outperforming benchmarked standard silicon substrates.
Mechanical strength has also been improved. TaiRay wafers show enhanced bending resistance, opening possibilities for thinner wafer applications without compromising module durability. Performance trials across multiple technologies validate TaiRay’s advantages. In TOPCon production lines, TaiRay wafers showed clear pathways to higher cell efficiencies by better matching resistivity to process requirements. In TBC and HBC lines, preliminary results suggest a significant uplift in performance potential. In HJT applications, where lifetime uniformity is crucial, TaiRay demonstrated notable improvements, even across longer ingot runs.
This text is an excerpt from the TaiyangNews Cell & Module Technology Trends 2025 report, which can be downloaded for free here.
