Thin film solar cell manufacturing and integration
View Patent ↗A method of forming a Group IBIIIAVIA solar cell absorber which includes an active portion and an electrically resistive portion. The absorber is interposed between a base layer and a transparent conductive layer. The electrically resistive portion increases resistance between the base layer and a connector layer that is formed on the transparent conductive layer. The connector layer comprises the busbar and the fingers of the solar cell. The busbar is preferably placed over the electrically resistive portion while the fingers extend over the active portion of the absorber layer.
1. A solar cell structure, comprising:
a base;
a single contiguous layer formed on the base, the single contiguous layer including a first portion and a second portion that is adjacent to and different than the first portion such that each of the first and the second portions are each formed on the base and the second portion forms a pattern, wherein the electrical resistivity of the second portion is higher than the electrical resistivity of the first portion, wherein the first portion forms an absorber to receive light, and wherein and the first portion comprises a Group IA material while the second portion does not contain the Group IA material;
a transparent conductive layer formed on the single contiguous layer; and
a metallic connector formed on the transparent conductive layer, the metallic connector having a primary connector and secondary connectors attached to the primary connector, wherein the primary connector is substantially positioned over the pattern formed by the second portion of the single contiguous layer that is adjacent to the first portion of the single contiguous layer without extending over the first portion of the single contiguous layer.
2. The structure of claim 1 , wherein the first portion includes at least one Group IB material, at least one group IIIA material and at least one Group VIA material, and wherein the second portion includes at least two materials from a set of materials including at least one Group IB material, at least one group IIIA material and at least one Group VIA material.
3. The structure of claim 2 , wherein the Group IB material comprises Cu, the Group IIIA material comprises at least one of In and Ga, and the Group VIA material comprises at least one of Se and S.
4. The structure of claim 3 , wherein the transparent conductive layer is a transparent conductive oxide layer.
5. The structure of claim 4 further including a buffer layer between the transparent conductive oxide layer and the layer.
6. The structure of claim 1 , wherein the primary connector includes a bulbar, and the secondary connectors include fingers.
7. The structure of claim 1 , wherein the base includes a substrate and a contact layer and the layer is formed over the contact layer.
8. The structure of claim 7 , wherein the substrate is a metallic foil.
9. The structure of claim 1 , wherein the Group IA material is one of Li, Na and K.
10. A solar cell structure, comprising:
a base;
a layer formed on the base, and including a first portion and a second portion that is adjacent to and different than the first portion such that each of the first and the second portions are each formed on the base and the second portion forms a pattern, wherein the first portion includes at least one Group IB material and at least one Group IIIA material, wherein the second portion includes at least one Group IB material and at least one Group IIIA material, wherein the molar ratio of Group IB material to Group IIIA material in the second portion is lower than the molar ratio of Group IB material to Group IIIA material in the first portion, and wherein the electrical resistivity of the second portion is higher than the electrical resistivity of the first portion, and wherein the first portion forms an absorber layer;
a transparent conductive layer formed on the layer; and
a metallic connector formed on the transparent conductive layer, the metallic connector having a primary connector and secondary connectors attached to the primary connector, wherein the primary connector is substantially positioned over the pattern formed by the second portion of the layer that is adjacent to the first portion of the layer without extending over the first portion of the layer.
11. The structure of claim 10 , wherein the molar ratio of Group IB material to Group IIIA material in the second portion is less than 0.8 and the molar ratio of Group IB material to Group IIIA material in the first portion is more than 0.8.
12. The structure of claim 10 , wherein the primary connector includes a busbar, and the secondary connectors include fingers.
13. The structure of claim 10 , wherein the base includes a substrate and a contact layer and the layer is formed over the contact layer.
14. The structure of claim 13 , wherein the substrate is a metallic foil.
15. The structure of claim 10 , wherein the Group IB material comprises Cu, the Group IIIA material comprises at least on of In and Ga, and wherein the first portion and the second portion further include a Group VIA material that comprises at least one of Se and S.
16. The structure of claim 15 , wherein the transparent conductive layer is a transparent conductive oxide layer.
17. The structure of claim 16 , further including a buffer layer between the transparent conductive oxide layer and the layer.
18. The structure of claim 10 , wherein at least the first portion further comprises a Group IA material.
19. The structure of claim 18 , wherein the Group IA material is one of Li, Na and K.