Methods of making photovoltaic devices

1. A method of making a photovoltaic device, comprising:

disposing an absorber layer on a window layer;

treating at least a portion of the absorber layer with a dopant solution comprising a dopant metal salt to form a first component, after the step of disposing the absorber layer on the window layer, wherein the step of treating at least a portion of the absorber layer with a dopant solution consists essentially of a soaking treatment wherein a portion of the absorber layer is soaked in the dopant solution, and wherein the dopant metal salt comprises a metal dopant selected from the group consisting of manganese, cobalt, chromium, zinc, indium, tungsten, molybdenum, and combinations thereof;

treating at least a portion of the first component with cadmium chloride to form a second component, wherein the second component comprises a doped absorber layer; and

contacting at least a portion of the second component with an aqueous mixture of ethylene diamine after the step of treating at least a portion of the first component with cadmium chloride.

2. The method of claim 1 , wherein the metal dopant comprises manganese.

3. The method of claim 1 , wherein the metal dopant comprises zinc.

4. The method of claim 1 , wherein the dopant metal salt comprises a metal chloride.

5. The method of claim 1 , wherein treating at least a portion of the first component with cadmium chloride further comprises a heating treatment.

6. The method of claim 5 , wherein the treating at least a portion of the first component with cadmium chloride includes a step of contacting at least a portion of the first component with cadmium chloride and the heating treatment is performed subsequent to the step of contacting at least a portion of the first component with cadmium chloride.

7. The method of claim 1 , wherein the treating at least a portion of the first component with cadmium chloride includes treating with a solution of cadmium chloride.

8. The method of claim 1 , wherein the treating at least a portion of the first component with cadmium chloride includes treating with a cadmium chloride vapor.

9. The method of claim 1 wherein the photovoltaic device has an open circuit voltage in a range greater than about 800 mV.

10. A method of making a photovoltaic device, comprising:

disposing an absorber layer on a window layer;

treating at least a portion of the absorber layer with cadmium chloride and heating the absorber layer;

contacting at least a portion of the absorber layer with an aqueous mixture of ethylene diamine; and

disposing an interfacial layer on the absorber layer, after the contacting step, by treating at least a portion of the absorber layer with an ohmic solution comprising an ohmic metal salt wherein the action of treating at least a portion of the absorber layer with an ohmic solution consists essentially of a soaking treatment wherein a portion of the absorber layer is immersed in the ohmic solution, and,

wherein the ohmic metal salt comprises an ohmic metal selected from the group consisting of: manganese, cobalt, nickel, zinc, and combinations thereof, and

wherein the ohmic metal is present in the interfacial layer at a concentration in a range less than about 1 atomic percent of the interfacial layer, and

wherein the interfacial layer has a thickness in a range from about 1 nanometer to about 50 nanometers.

11. The method of claim 10 , wherein the ohmic metal comprises manganese.

12. The method of claim 10 , wherein the ohmic metal comprises zinc.

13. The method of claim 10 , wherein the ohmic metal salt comprises a metal chloride.

14. The method of claim 10 , wherein treating at least a portion of the absorber layer with cadmium chloride includes treating with a solution of cadmium chloride.

15. The method of claim 10 , wherein treating at least a portion of the absorber layer with cadmium chloride includes treating with a vapor of cadmium chloride.

16. The method of claim 10 , wherein treating at least a portion of the absorber layer with an ohmic solution further includes forming a telluride of the ohmic metal such that the interfacial layer includes at least one of manganese telluride, zinc telluride, cobalt telluride, nickel telluride.

17. The method of claim 10 , wherein the ohmic metal is present in the interfacial layer at a concentration in a range from about 0.05 atomic percent to about 5 atomic percent.

18. A method of making a photovoltaic device, comprising:

disposing an absorber layer on a window layer;

disposing an interfacial layer on the absorber layer after the step of disposing the absorber layer on the window layer by treating at least a portion of the absorber layer with an ohmic solution comprising an ohmic metal salt wherein the action of treating at least a portion of the absorber layer with an ohmic solution consists essentially of a soaking treatment wherein a portion of the absorber layer is immersed in the ohmic solution, and,

wherein the ohmic metal salt comprises an ohmic metal selected from the group consisting of manganese, cobalt, nickel, zinc, and combinations thereof, and

wherein the ohmic metal is present in the interfacial layer at a concentration in a range less than about 1 atomic percent of the interfacial layer,

wherein the interfacial layer has a thickness in a range from about 1 nanometer to about 50 nanometers, and

wherein the interfacial layer is enriched in tellurium such that an atomic concentration of tellurium in the interfacial layer is greater than about 60 atomic percent.