Choice of the low-temperature sintering Ag paste for a-Si:H/c-Si heterojunction solar cell based on characterizing the electrical performance

• How to get excellent electrical performance for low-temperature Ag paste was studied.
• The paste should be made of nano-sized silver particles.
• The binder resin content in the paste should be low.
• The organic solvents with low boiling point are easy burnt out at low temperature.
• Uniform distribution of Ag nanoparticles in the organic network is very beneficial.

Four different low-temperature sintering silver pastes were utilized to make the metal grids for a-Si:H/c-Si heterojunction (SHJ) solar cells. The thermal characteristics, the microstructure and the preferential growth orientation of the four pastes were comparatively investigated between before and after sintering. The evolution of the electrical performance of the grids as well as its effects on the performance of the SHJ solar cells was also analyzed. Based on the results, we clarified some requirements on the compositions, the morphology, and the microstructure of the low-temperature Ag paste for the SHJ solar cell application. Uniformly distributed nanoscale Ag paste with suitable organic solvents should be the best.