New Efficiency Record: TOPCon Solar Cells Achieve 26.66% Power Conversion

TOPCon solar cell technology, a type of crystalline silicon solar cell, is a widely used and growing segment of the global photovoltaic industry. Historically, its mass-production efficiency has been below its theoretical limit due to electrical performance constraints. Researchers in China have now achieved a new power conversion efficiency (PCE) record of 26.66% for industrial-scale TOPCon solar cells.

This new power conversion efficiency (PCE) record of 26.66% for industrial-scale TOPCon solar cells marks a significant advancement for the technology.

Collaborative Research Details

The groundbreaking study was led by Prof. YE Jichun from the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences. The research involved key collaborations with Zhejiang Jinko Solar Co., Ltd., Soochow University, and China Jiliang University. The significant findings were officially published in the esteemed journal Nature Energy on February 24.

Dual-Side Refinement Strategy Unlocks New Efficiency

The core of this breakthrough lies in a sophisticated dual-side electrical refinement strategy. This innovative approach was specifically applied to large-area TOPCon solar cells, utilizing an M10 wafer with an effective area of 313.3 cm2.

Enhanced Front Side Design

On the front side of the solar cell, the researchers implemented high-sheet-resistance boron emitters, measured at approximately 430 Ω sq-1. This was combined with meticulously optimized grid designs. This dual enhancement significantly improved surface passivation and effectively reduced carrier transport losses, boosting overall performance.

Innovative Rear Side Structure

For the rear side, a novel double-layer tunnel oxide/polysilicon structure was developed. This design is crucial for mitigating metallization-induced degradation. The structure features a highly crystalline inner polysilicon layer and an outer barrier layer, specifically engineered to prevent silver diffusion from the electrodes into the silicon substrate. This ensures effective interfacial passivation, which is vital for maintaining efficiency over time.

Strategic thinning of the rear polysilicon layer further enhanced the cell's bifaciality, reaching an impressive 88.3%. This improvement translates directly to a higher overall energy yield. These combined innovations ultimately enabled the industrial TOPCon solar cell to achieve an impressive open-circuit voltage (Voc) of 744.6 mV and a fill factor (FF) of 85.57%.

Record Efficiency and Future Outlook

Prof. YE Jichun, a corresponding author of the study, highlighted the magnitude of this achievement, stating that the device has reached 83.8% of the theoretical efficiency limit, significantly surpassing the performance of conventional TOPCon solar cells.

"The device has reached 83.8% of the theoretical efficiency limit, surpassing the performance of conventional TOPCon solar cells," stated Prof. YE Jichun.

This research not only establishes a new benchmark but also provides a clear pathway for manufacturing even higher-efficiency industrial TOPCon cells. The breakthrough effectively narrows the gap between current practical efficiency and theoretical limits, which is anticipated to substantially enhance the technology's competitiveness in the global photovoltaic market.