Fabrication of metal grid on silicon-based solar cell by electrochemical deposition and microcontact print

This work presents a novel and low-cost printing technique to construct a three-layer (Pd/Ni/Cu) structure as front side conductor of textured mono-crystalline silicon solar cells. The technique involves microcontact printing and electrochemical deposition. Electrochemical deposition including electroless Ni and electroplated Cu offers an inexpensive method in contrast to the conventional silver-paste. The first step of this technique is activation by Pd nanoparticles. The Pd nanoparticles with average particle size about 2.65 nm are then mixed with organic solvent to prepare Pd ink. Then we imprint Pd ink on the front side of solar cell by microcontact printing, which can print fine-lines of less than 60 μm width. The second layer is electroless nickel providing low contact resistance and good mechanical adhesion. The third layer is electrodeposited Cu to increase the line conductivity. X-ray diffraction (XRD) technique and secondary electron microscopy (SEM) were employed to detect the presence of nickel-silicides phase after annealing. This new scheme has proven to be workable and may become an alternative approach for surface metallization on solar cell.