JTPV has progressed its TOPCon technology from MoNo1 to MoNo3 since 2024
TBC cell efficiency reached 27.1% on average, with a 27.4% champion cell in July 2026
The company estimates that 40% of equipment can be reused when converting a 4 GW TOPCon line to TBC
Xinrui An, R&D Manager at Jietai Solar (JTPV), presented the company’s progress in its TOPCon and back contact (BC) cell technologies at the TaiyangNews Cell & Module Production Equipment and Processing Materials Conference.
He discussed the developments that upgraded JTPV’s TOPCon cells, starting from 2024. Marketed as MoNo1, this generation of TOPCon product included material and process developments, such as fine metallization fingers, super multi busbars (SMBB), emitter metal contact optimization, gradient-index anti-reflective coating (ARC), and stacked wafer deposition process. The average cell efficiency at the time was about 25.5%.
Progressing from MoNo1, the company launched MoNo2 in 2025, which included polyfingers on the rear side, which the company describes as wave back-surface field (WBSF), and passivating the cut edges. An said that these developments contributed to about a 0.5% increase in efficiency and 6% in bifaciality at the cell level when compared to MoNo1. Additionally, the module power improved by 5-8 W with MoNo2 cells.
Further improving the MoNo2, JTPV recently reached the final stage of pilot production with MoNo3 technology. This product includes developments at both cell and module levels. At the cell level, it implemented silver-lean metallization, which uses silver-coated copper paste solution and fine-line printing. The company also implemented its ‘cut line technology’ (CLT), a process in which the emitter near the laser-cut positions is locally removed, followed by passivation with aluminum oxide and silicon nitride (see Cut Line Technology Targets Edge Losses In Multi-Cut TOPCon Cells). At the module level, JTPV used a multi-cut cell configuration with an overlapping cell interconnection method. Using MoNo3 cells on 213 × 182 mm wafer formats, the module power was increased by 8-10 W.
An also discussed JTPV’s BC technology development: the company started working on TBC (TOPCon-based BC) in 2023, with an initial cell efficiency of 25%, which improved to 27%. The technology reached an average cell efficiency of 27.1% in July 2026, with a champion cell achieving 27.4% efficiency. Module power using these cells also improved to 660 W from 640 W, according to An.
Compared with mainstream pad soldering, the company also implements full-line soldering where the ribbon is directly soldered to the cell fingers, without busbars (0BB). JTPV’s BC also includes other developments, including optimization of the wet chemistry process, laser patterning of boron-doped polysilicon (p-poly region), and front-side texturization, achieving an iVoc of about 753 mV. To address the lower bifaciality of BC cells vis-à-vis TOPCon, the company used stencil printing for a finer metallization grid and reduced the polysilicon layer thickness to reduce parasitic absorption. With these steps, the bifaciality was increased to 75%. The cells made with these developments are described as TBC 2.0 by JTPV. This generation of BC also involves processing half-cut cells, meaning the silicon nitride and aluminum oxide layers are deposited on partially processed half-cut wafers, which also naturally passivate the exposed or cut edges. In its BC roadmap, JTPV also plans to further optimize the architecture to use hybrid passivation approach that involves TOPCon and HJT passivated polarities.
The company estimated the cost of converting a 4 GW 182 mm TOPCon line to a 210R TBC line and found that 40% of its equipment can be reused for the upgraded line, with an investment of RMB 80 million per GW of capacity conversion.
