A research team led by Prof. YE Jichun from the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences, in collaboration with partners, has proposed a synergistic technical solution enabling industrial tunnel oxide passivating contact (TOPCon) solar cells to simultaneously achieve high efficiency, low cost, and excellent bifacial power generation performance. The study was published in the journal Joule on December 12.

As a mainstream photovoltaic technology in the current crystalline silicon photovoltaic market, TOPCon solar cells account for over 70% of the global market share, driven by their high power conversion efficiency (PCE), cost competitiveness, and mass production feasibility.

However, their industrial advancement is hindered by pressing challenges, including high silver paste consumption,parasitic optical loss, and limited bifacial performance—all of which impede further efficiency improvements and cost reduction efforts.

To address these issues, the research team developed a technical solution directly applicable to mass production. Utilizing industrial M10 silicon wafers, the solution employs a high-precision steel-stencil printing process to fabricate the front metal fingers of the cells, while integrating a localized polysilicon contact structure on the rear side.

The front-side steel-stencil printing process enables the production of ultra-narrow metal fingers, reducing the cells' silver paste consumption by 0.12 mg per watt (mg/W). When combined with a modified silver paste, this process forms dense nanosilver clusters at the contact interface between the electrodes and silicon wafers, lowering contact resistivity to 2.4 milliohm-centimeters (mΩ·cm²).

Meanwhile, the localized structure design on the rear side effectively minimizes parasitic optical absorption, boosting the cell's bifaciality to approximately 90%.

Through these innovations, the team successfully fabricated an industrial TOPCon solar cell with a certified PCE of 26.09%. This strategy breaks the traditional trade-offs between efficiency, cost, and bifacial performance—a key constraint in previous TOPCon development.

This work provides a viable and scalable solution for manufacturing high-performance, low-cost TOPCon cells.

The high-efficiency industrial TOPCon solar cells. (Image by NIMTE)