Juan Hong,Jianxin Sun,Xin Liu,Yixuan Huang,Longqing Jiang,Shuangyu Liu,Feng Qian,Shen Honglie,Yang Yang,Rulong Chen,Guanghua Song
In the present study, we establish a physical model for laser-assisted localized boron doping in N-type tunnel oxide passivated contact (TOPCon) solar cells by employing the fluid dynamics method. Our simulations reveal that a flat-top beam inflicts less thermal damage on silicon than a Gaussian beam at a constant laser energy density. Additionally, we observe an acceleration in the flow rate of molten silicon in the molten pool as the laser energy density increases. This acceleration facilitates efficient doping of boron atoms into the silicon substrate, albeit accompanied by an expansion of the local thermal damage range. In light of these findings, we utilized boron-doped silicon paste as a doping source in experiments conducted on a 15 MW TOPCon solar cells production line employing four distinct laser energy densities. The experiments yielded a reduction in the sheet resistance to 81.9 Ω/cm in the boron-doped regions, an increase in the peak boron doping concentration to 1.08 × 10
19
atoms/cm
3
, and a doping depth of 2.38
μ
m. Consequently, the highest efficiency enhancement recorded was 0.14%, culminating in an efficiency of 25.06%. This research outlines the mechanism of the laser-assisted localized boron doping process and provides insights for enhancing the efficiency of TOPCon solar cells.
Filtration is a pivotal industrial technology that enables the efficient separation and purification of multiphase systems while optimizing resource utilization, improving operational efficiency, and addressing environmental sustainability challenges. However, developing filtration systems that deliver high clarity and rapid filtration rates, while resisting surface cracks in multiphase unstable polysilicon slurry remains a significant challenge. In this work, a cellulose-modified diatomite-based dipole-interaction-enhanced (CE@D-IE) strategy, characterized by its straightforward yet highly effective, was proposed as a solution to the issue. The CE@D-IE filtration system prevented filter cake from surface cracking at 10-40 °C, attributed to diatomite's capillary resistance, cellulose-enhanced dipole interactions, and chain entanglement. Atomic force microscopy (AFM) and molecular dynamics (MD) simulations further revealed stronger interaction within the filter cake formed by the CE@D-IE strategy, providing critical molecular-level evidence for its improved resistance to surface cracking. Furthermore, the CE@D-IE strategy achieved excellent filtrate clarity and demonstrated a 50% improvement in filtration rate compared to the BF strategy, resulting in a comprehensive enhancement of polysilicon slurry filtration performance . This work provides a viable and practical solution to address filtration challenges in polysilicon slurry under complex and dynamic conditions, while also demonstrating significant potential to enhance filtration performance in other complex systems.
Chong He,Xinger Liu,Cong Ma,Yueqi Cao,Feng Hou,Liwen Yan,Anran Guo,Jiachen Liu
Nowadays, 3D polymer-derived silicon oxycarbide ceramics (SiOC) can be fabricated by the stereolithography method successfully. However, due to their intrinsically poor ceramic content and the large thermal shrinkage during the pyrolysis, it is difficult for the bulk 3D polysiloxane precursors to be pyrolyzed into dense 3D-ceramics. Herein, the ceramic content of the photocurable polysiloxane precursors was increased by adding a large amount of SiO 2 powders into the low solid content epoxy-acrylic siloxane. After being added with proper dispersant, the viscosity of the high solid loading polysiloxane/SiO 2 slurry can reach a proper level. Bulk 3D-silica ceramics with the wall-thickness around 8 mm can be conveniently fabricated from the polysiloxane/SiO 2 slurry by stereolithography and a two-step sintering process. The addition of a proper sintering aid NaF can promote the 3D-PSO/SiO 2 precursor to be converted into dense and crack-free 3D-silica ceramics with good mechanical proprieties.
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