Microstructural investigation of new thick-film paste flux for contacting silicon solar cells

This paper discusses a microstructural investigation of p-type crystalline silicon (c-Si) solar cells printed with a newly developed screen-printable paste flux additive, which demonstrates better cell performance compared to current industry-standard commercial pastes. Advanced electron microscopy techniques were used to study in detail the microstructure of the front-side (FS) Ag contact interface region of c-Si cells printed with either the paste containing the new flux additive or a commercial paste. Our results reveal that solar cells fabricated with the new flux additive paste had more uniform and longer regions of ultra-thin interfacial glass at the FS Ag-silicon interface, which results in improved series resistance and reduced emitter/junction damage. The current conduction mechanism of FS contact of c-Si solar cells made with this new paste is described.