Preparation and sintering behavior of micron-sized spherical-like sliver particles based on seed-mediated method

Tunneling oxide passivated contact (TOPCon) solar cells are conventionally sintered at lower temperatures using the laser enhanced contact optimization (LECO) process, which requires higher sintering activity of silver particles. In this study, spherical-like silver particles were synthesized based on a seed-mediated method using ascorbic acid to reduce silver nitrate. In addition, by mediated growth after the seed modification treatment, pores are formed inside the silver particles and the grain size is reduced. The pore and grain sizes of silver particles were characterized and analyzed using electron backscatter diffraction (EBSD) and small angle X-ray scattering (SAXS). The creation of defects in modified seed-mediated diffusive growth leads to the appearance of pore structures within the particles. Thermo-mechanical analysis (TMA) showed that the contraction rate of silver particles increased from 12.35 % to 13.61 % in the presence of internal pores, indicating high sintering activity. The modified seed-mediated silver particles were formulated into silver pastes, exhibiting a lower line resistivity of 2.342 μΩ·cm.