KH550 and Sodium Palmitate Mediated Synergistic Modification of Micronized Silver Powder: Insights into Dispersion Regulation and TOPCon Paste Performance Optimization.

Micron-sized silver powder plays a crucial role in Tunnel Oxide Passivated Contact solar cells (TOPCon) within the photovoltaic field due to its high bulk density and excellent rheological properties. Considering that micron-sized silver powder produced by the liquid-phase reduction method exhibits characteristics such as high surface energy and a tendency to agglomerate, along with poor compatibility with organic carriers in the paste, this work employs a strategy of synergistically modifying micron-sized silver powder with KH550 and sodium palmitate to regulate silver powder dispersion and paste adaptability. The composite-modified silver powder exhibits an increase in tapped density from 4.25 g/cm3 to 6.01 g/cm3, a bulk density elevated from 2.98 g/cm3 to 4.11 g/cm3, and a contact angle increased from 46° to 141.5°, demonstrating significantly enhanced dispersion. The TOPCon silver paste prepared from the modified silver powder exhibited excellent comprehensive properties: a viscosity of 6.43 × 106 cp, a low resistivity of 2.75 × 10-6 Ω·cm, and a high aspect ratio of 45.18%. This work elucidates the impact of surface multifunctionalization on silver powder dispersion and paste compatibility, offering a novel approach for designing surface-functionalized micron-sized silver powder and developing high-performance electronic pastes.