Mitigating Laser-Induced Defects in Silicon Heterojunction Solar Cells

Strategic Insights -

Recent research by Zhejiang University has made significant breakthroughs in understanding the mechanisms of laser-induced defects in silicon heterojunction solar cells. The study, funded by the National Natural Science Foundation of China and the "Pioneer" and "Leading Goose" R&D Program of Zhejiang, has shed light on the effects of thermal laser separation (TLS) on the microstructure of these high-efficiency photovoltaic cells.

The research has highlighted the crucial role of edge passivation in minimizing cell-to-module losses, but it also revealed that performance degradation persists even with this technique. To address this issue, the study employed high-resolution scanning transmission electron microscopy (STEM) to examine the changes in the microstructure of the cells. The results showed that the hydrogenated amorphous silicon (alpha-Si:H) layer near laser-cut edges crystallizes, leading to defects in the crystalline silicon (c-Si) regions. The scribing laser also melted and diffused the indium tin oxide (ITO) layer, causing further defects.

Key Takeaways:

  • The study focused on the effects of TLS on the microstructure of silicon heterojunction solar cells, highlighting the importance of understanding these changes for future PV markets.
  • The research revealed that the crystallization of the alpha-Si:H layer near laser-cut edges is responsible for defects in the c-Si regions, resulting in reduced module efficiency.
  • The scribing laser's melting and diffusion of the ITO layer also contributed to defects in the c-Si regions, posing a significant challenge for large-scale production.
  • The study's findings highlight the need for strategies to mitigate laser-induced defects and enhance SHJ cell efficiency and reliability.
  • The research has been peer-reviewed and published in the Journal of Engineering.

Statistics:

  • The alpha-Si:H layer near laser-cut edges crystallizes over an affected zone spanning approximately 12 μm at the n+-n junction and 6 μm at the p+-n junction.
  • The scribing laser melts and diffuses the ITO layer, inducing defects in the c-Si regions over an estimated 12 μm.
  • The study recommends developing strategies to mitigate laser-induced defects to enhance SHJ cell efficiency and reliability for large-scale production.

Sources:

  • NewsRx. Findings from Zhejiang University in Technology Reported (Transmission Electron Microscopy Study On the Laser-cutting Induced Microdefects In Silicon Heterojunction Solar Cells). Journal of Engineering. October 20, 2025; p 888.
  • Zhejiang University, School of Materials Science and Engineering, State Key Lab Silicon & Adv Semicond Mat, Hangzhou 310027, Zhejiang, People's Republic of China.
  • National Natural Science Foundation of China (NSFC).
  • The "Pioneer" and "Leading Goose" R&D Program of Zhejiang.