A method is disclosed for fabricating high efficiency CIGS solar cells including the deposition of a multi-component metal precursor film on a substrate. The substrate is then inserted into a system suitable for exposing the precursor to a chalcogen to form a chalcogenide TFPV absorber. One or more Na precursors are used to deposit a Na-containing layer on the precursor film in the system. This method eliminates the use of dedicated equipment and processes for introducing Na to the TFPV absorber.