Photovoltaic devices and method of making

1. A photovoltaic device, comprising:

a transparent conductive oxide layer;

a semiconducting layer;

a buffer layer interposed between the transparent conductive oxide layer and the semiconducting layer; and

an interlayer comprising a metal species disposed directly in contact with the buffer layer between the transparent conductive oxide layer and the semiconducting layer, wherein:

the metal species comprises gadolinium, beryllium, calcium, barium, strontium, scandium, yttrium, hafnium, lutetium, lanthanum, or combinations thereof,

an average atomic concentration of the metal species in the interlayer is in a range from about 10 percent to about 99 percent, and

the interlayer has a thickness in a range from about 0.2 nanometers to about 200 nanometers.

2. The photovoltaic device of claim 1 , wherein at least a portion of the metal species is present in the interlayer in the form of an elemental metal, a metal alloy, a metal compound, or combinations thereof.

3. The photovoltaic device of claim 1 , wherein the semiconducting layer comprises cadmium sulfide, oxygenated cadmium sulfide, zinc sulfide, cadmium zinc sulfide, cadmium selenide, indium selenide, indium sulfide, indium III sulfide, zinc telluride, zinc selenide, copper oxide, zinc oxihydrate, or combinations thereof.

4. The photovoltaic device of claim 1 , wherein the interlayer further comprises tin, sulfur, oxygen, fluorine, zinc, cadmium, or combinations thereof.

5. The photovoltaic device of claim 1 , wherein the interlayer comprises a metal compound comprising the metal species, tin, and oxygen, or a metal compound comprising the metal species and fluorine.

6. The photovoltaic device of claim 1 , wherein:

the transparent conductive oxide layer comprises cadmium tin oxide, zinc tin oxide, indium tin oxide, fluorine-doped tin oxide, indium-doped cadmium-oxide, doped zinc oxide, or combinations thereof; and

the buffer layer comprises tin dioxide, zinc oxide, indium oxide, zinc tin oxide, or combinations thereof.

7. The photovoltaic device of claim 1 , further comprising an absorber layer disposed on the semiconducting layer, wherein the absorber layer comprises cadmium telluride, cadmium zinc telluride, cadmium sulfur telluride, cadmium selenium telluride, cadmium manganese telluride, copper indium sulfide, copper indium gallium selenide, copper indium gallium sulfide, or combinations thereof.

8. The photovoltaic device of claim 7 , further comprising a secondary interlayer interposed between the semiconducting layer and the absorber layer, wherein the secondary interlayer comprises magnesium, aluminum, zinc, nickel, gadolinium, or combinations thereof.

9. The photovoltaic device of claim 1 , wherein the interlayer has a thickness in a range from about 0.2 nanometers to about 20 nanometers.

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

disposing a buffer layer over a transparent conductive oxide layer;

disposing an interlayer comprising a metal species adjacent the buffer layer, wherein:

the interlayer has a thickness in a range from about 0.2 nanometers to about 200 nanometers;

the metal species comprises gadolinium, beryllium, scandium, yttrium, hafnium, lutetium, lanthanum, calcium, barium, strontium, or combinations thereof; and,

an average atomic concentration of the metal species in the interlayer is in a range from about 10 percent to about 99 percent;

disposing a semiconducting layer over the interlayer; and

disposing an absorber layer over the semiconducting layer.

11. The method of claim 10 , further comprising interposing a secondary interlayer between the semiconducting layer and the absorber layer, wherein the secondary interlayer comprises magnesium, aluminum, zinc, nickel, gadolinium, or combinations thereof.

12. The method of claim 10 , wherein the absorber layer comprises cadmium telluride, cadmium zinc telluride, cadmium sulfur telluride, cadmium selenium telluride, cadmium manganese telluride, cadmium magnesium telluride, copper indium sulfide, copper indium gallium selenide, copper indium gallium sulfide, or combinations thereof.

13. The method of claim 10 , wherein the semiconducting layer comprises cadmium sulfide, oxygenated cadmium sulfide, zinc sulfide, cadmium zinc sulfide, cadmium selenide, indium selenide, indium sulfide, indium III sulfide, zinc telluride, zinc selenide, copper oxide, zinc oxihydrate, or combinations thereof.

14. The method of claim 10 , wherein the interlayer has a thickness in a range from about 0.2 nanometers to about 20 nanometers.

15. A photovoltaic device, comprising:

a buffer layer disposed on a transparent conductive oxide layer;

a semiconducting layer disposed on the buffer layer;

an interlayer comprising a metal species interposed between the buffer layer and the semiconducting layer, wherein at least a portion of the metal species is present in the interlayer in the form of an elemental metal, and wherein the metal species comprises gadolinium, beryllium, calcium, barium, strontium, scandium, yttrium, hafnium, cerium, lutetium, lanthanum, or combinations thereof;

an absorber layer disposed on the semiconducting layer; and

a back contact layer disposed on the absorber layer.

16. The photovoltaic device of claim 15 , wherein the semiconducting layer comprises cadmium selenide.

17. The photovoltaic device of claim 1 , wherein the interlayer comprises Gd x Sn 1-x , wherein x is a number greater than 0 and less than 1.

18. The photovoltaic device of claim 1 , wherein an average atomic concentration of the metal species in the interlayer is in a range from about 50 percent to about 99 percent.

19. The photovoltaic device of claim 1 , wherein the interlayer is disposed between the buffer layer and the transparent conductive oxide layer.

20. The photovoltaic device of claim 1 , wherein the interlayer is disposed between the buffer layer and the semiconducting layer.