Preparation of the lead-free graphene-glass frit composites for crystalline silicon solar cells and investigation of performance

The lead-free glass frit is prepared by melt-quenching method, and then the graphene oxide (GO) was sufficiently mixed with the glass frit. Finally, by a reduction reaction, the lead-free graphene-glass frit composites is obtained. When the reducing agent selected is diethylene glycol, scanning electron microscope (SEM) analysis shows that graphene is evenly compounded in the glass frit. When the composites are put into use to the front contact electrode of the crystalline silicon solar cells, the mass ratio of graphene oxide to the lead-free glass frit is preferably 0.05. At this time, due to the sheet-like structural characteristics of the graphene, the gap left by the shrinkage of the silver paste is well filled after the printing and sintering, so that the surface of the silver grid line is the smoothest, dense, and the tensile force with the silicon substrate is also the largest. The series resistance Rs of the battery is significantly lowered, and the photoelectric conversion efficiency Eff of the solar cell is improved.