Cu2ZnSn(S,Se)4 solar cell absorbers processed from Na-containing solutions in…

Cu2ZnSn(S,Se)4 absorbers were processed from metal salt solutions in dimethyl sulfoxide (DMSO) and annealed in reactive Se atmosphere. A simple way to introduce sodium doping by adding NaCl to the initial precursor solution is presented. The additional sodium has no significant effect on the absorber morphology, but it improves the device performance from 5.01% to 6.09%. The sodium doping clea…