NOVELTY - Making (M1) a photovoltaic absorber on a substrate involves: (a) providing substrate coated with electrical contact layer; (b) depositing one layer of first precursor ink onto substrate; (c) heating substrate, thereby converting first precursor ink to first film material on substrate; (d) repeating steps b) and c); (e) annealing substrate; (f) repeating steps b) and c), where each repetition uses additional precursor ink having different concentration of Group 13 atom; (g) annealing third film material, thereby creating final film material on substrate.    USE - For making photovoltaic absorber on substrate (claimed); for making solar cells having high efficiencies for conversion of light.    ADVANTAGE - The process have a well-defined compositional gradient by providing alkali free zones which prevent or suppress the diffusion or transport of certain atoms.    DETAILED DESCRIPTION - Making (M1) a photovoltaic absorber on a substrate involves: (a) providing a substrate coated with an electrical contact layer; (b) depositing one layer of a first precursor ink onto the substrate, where the ink has a first concentration of a Group 13 atom; (c) heating the substrate, thereby converting the first precursor ink to a first film material on the substrate; (d) repeating steps b) and c) from zero to twenty times, thereby creating a second film material on the substrate; (e) annealing the substrate; (f) repeating steps b) and c), where each repetition uses an additional precursor ink having a different concentration of the Group 13 atom as any of the earlier steps, thereby creating a third film material; (g) annealing the third film material, thereby creating a final film material on the substrate having a concentration gradient for the Group 13 atom. INDEPENDENT CLAIMS are included for the following:    (1) a photovoltaic absorber made by the method (M1);    (2) making (M2) a photovoltaic absorber layer on a substrate involving: (a) providing a substrate; (b) forming a layer of a first material on the substrate, where the first material has a first concentration of a Group 13 atom and the first material contains alkali ions; (c) forming a layer of a second material onto the first material, where the second material has a second concentration of a Group 13 atom that is the same or different from the first concentration, where the second material is free from alkali ions; and    (3) a photovoltaic absorber comprising a thin film material on a substrate, where at least a portion of the thin film material has a gradient of the concentration of a Group 13 atom in a direction normal to the substrate.