Electroless silver plating on the surface of glass frits and its application in solar cells

Glass frits were activated through the process of ethylene glycol reducing silver nitrate with the assistance of ultrasound, and then nano-silver coated glass frits were prepared by electroless plating method at room temperature utilizing silver nitrate as silver source and tannic acid as reducing agent. The as-prepared composite powders were subsequently applied to silver paste for silicon solar cells. The morphologies and chemical constituents of the composite powders, the surfaces and cross sections of solar cell electrodes were characterized by SEM and EDS respectively. The structures and thermal behavior of glass frits were studied by XRD and DSC respectively. The results show that, under the specified reacting conditions, nano-silver particles of uniform size are evenly deposited on the surface of glass frits when the initial mass ratio of silver nitrate to glass frits is 0.09. The nano-silver coating on the glass frits contributes to lowing the glass transition temperature, densifying the electrode conductive films as well as promoting more silver crystallites to grow onto the silver-silicon interface during the cooling process. Compared with silicon solar cells prepared by using pure glass frits, the photoelectric conversion efficiency of solar cells prepared by using 9%Ag@GF is increased from 17.551% to 17.711%.