A spiking-resistant all-Al rear-junction n-type Si solar cell

In this paper we report a spiking-resistant all-Al rear junction n-type monocrystalline Si solar cell with an efficiency of 18%. This 1×1 inch 2 cell is fabricated by ionic liquid based electroplating of Al as the front electrode on an n-type Si solar cell with screen-printed Al as the rear junction. Partially-processed cells are prepared in an industrial R&D line of Canadian Solar. The cells are patterned by photolithography to open the front contact. A seed layer of Ni is deposited by sputtering to assist Al electroplating. A finished cell is annealed at different temperatures from 150–450°C to evaluate the effect of temperature on its performance. Compared to a p-type all-Al cell we reported before, the n-type all-Al cell is more resistant to high temperature Al spiking. Further comparison between this cell which has an electroplated Al front electrode and control cells with a screen-printed Ag front electrode demonstrates the feasibility of replacing Ag with electroplated Al as the front electrode.