Light Induced Plating of Silicon Solar Cells Using Boric Acid-Free Nickel Chemistry

Degradation of copper‐plated silicon solar cells with damp heat stress

“…I‐V measurements of Ag‐screenprinted and Cu‐plated modules over 4500 h of damp heat exposure, from two wafer manufacturers (Mfg A, left, and Mfg B, right). Ag‐screenprinted samples were fabricated entirely by the respective manufacturer, whereas for Cu‐plated samples, precursors lacking a front contact were manufactured by the manufacturer, with patterning and Cu‐plating performed later via the processes described in other references 24,25 . Patterning for Mfg A's plated cells was done via laser ablation, while wet‐chemical etch patterning was performed on Mfg B's cells.…”

“…For Cu‐plated cells, only the rear metallization is fired, after which patterning is performed on the front side. After patterning, the exposed bare silicon pattern is cleaned, then plated with a stack of nickel, copper, then tin, using the light‐induced plating (LIP) process described previously 24 . The initial layer of Ni serves a number of purposes: first, it is necessary as a barrier layer to prevent the diffusion of Cu (potentially a detrimental, lifetime‐limiting impurity in c‐Si).…”