High-efficiency cell structures for medium-quality silicon

The price of the silicon wafer is still ranking first in the cost distribution of a PV module. This main cost fraction can be reduced by either using thinner wafers or increasing cell efficiency. Both approaches require simplified high-efficiency structures suitable for industrial quality material. This paper gives an overview about recent activities in this research field and presents the latest results achieved at Fraunhofer ISE. New cell structures like the Emitter-Wrap-Through (EWT) cell, very thin high-efficiency cells, improved processing sequences reducing the defect concentration and a new patented process for the point contacts of dielectric passivated cells called Laser-Fired Contacts are discussed in detail.