Boosting Cu2ZnSnS4 solar cells efficiency by a thin Ag intermediate layer between absorber and back contact

In this work, 20 nm Ag is deposited on Mo coated soda lime glass prior to Cu2ZnSnS4 absorber deposition to improve the back contact and therefore enhance solar cell efficiency. This thin coating is found to inhibit the formation of SnS2, MoS2, and other defects especially voids at the back contact; therefore, reduces the series resistance and recombination leading to substantially higher short circuit current density (J(SC)), fill factor, open circuit voltage (V-OC), and efficiency in comparison to the controlled non-coating Mo, though the former results in lower material crystallinity. (C) 2014 AIP Publishing LLC.