Method for obtaining high performance thin film devices deposited on highly textured substrates
View Patent ↗The present invention provides an improved thin film solar cell, wherein at least one additional resistive transparent conductive oxide (TCO) layer is incorporated into the solar cell. The additional resistive TCO electrically separates the conductive TCO layers acting as electrodes of such a cell and thus decreases or prevents performance losses. Furthermore, methods for the production of such solar cells are disclosed.
1. A thin film solar cell, comprising:
a translucent substrate;
a textured TCO layer on the substrate;
an absorber layer on the textured TCO layer, the absorber layer having a pin structure;
a resistive TCO layer on the absorber layer; and
a second TCO layer on the resistive TCO layer,
wherein the absorber layer extends between the second TCO layer and the textured TCO layer,
wherein the resistive TCO layer is provided between the absorber layer and the second TCO layer such that a high resistance path is formed within the absorber layer, and
wherein a material of the resistive TCO layer has a resistivity that is greater than a resistivity of a material of the textured TCO layer and a resistivity of a material of the second TCO layer.
2. The solar cell according to claim 1 , further comprising:
a second resistive TCO layer disposed between the textured TCO layer and the absorber layer.
3. The solar cell according to claim 1 , wherein a texture of the textured TCO layer has a roughness of ≧30 nm and ≦600 nm.
4. The solar cell according to claim 1 , wherein the absorber layer comprises at least one pin structure comprising amorphous hydrogenated silicon.
5. The solar cell according to claim 1 , wherein a resistivity of the resistive TCO layer is greater than a resistivity of the textured TCO layer and a resistivity of the second TCO layer.
6. The solar cell according to claim 2 , wherein a resistivity of the second resistive TCO layer is greater than a resistivity of the textured TCO layer and a resistivity of the second TCO layer.
7. The solar cell according to claim 1 , wherein the resistive TCO layer comprises undoped ZnO.
8. The solar cell according to claim 2 , wherein the second resistive TCO layer comprises undoped ZnO.
9. An array of at least two solar cells according to any of claims 1 to 8 .
10. A method for the production of a thin film solar cell comprising the step of depositing at least one resistive TCO layer, wherein the deposited resistive TCO layer is located between a textured TCO layer and a second TCO layer of the thin film solar cell wherein the thin film solar cell comprises:
a translucent substrate;
the textured TCO layer on the substrate;
an absorber layer on the textured TCO layer, the absorber layer having a pin structure;
the resistive TCO layer on the absorber layer; and
the second TCO layer on the resistive TCO layer,
wherein the absorber layer extends between the second TCO layer and the textured TCO layer,
wherein the resistive TCO layer is provided between the absorber layer and the second TCO layer such that a high resistance path is formed within the absorber layer, and
wherein a material of the resistive TCO layer has a resistivity that is greater than a resistivity of a material of the textured TCO layer and a resistivity of a material of the second TCO layer.
11. The method according to claim 10 comprising the steps of:
a) providing a substrate with the textured TCO layer;
b) depositing an absorber layer; and
c) depositing the second TCO layer, wherein
at least one further resistive TCO layer is deposited so that the resistive TCO layer is located between the textured TCO layer and the second TCO layer of the thin film solar cell.
12. The method according to claim 11 , wherein deposition of the TCO layers is carried out by LPCVD.
13. The method according to claim 12 , wherein the deposition of the resistive TCO layer is carried out in a single LPCVD process together with the deposition of the second TCO layer.
14. The method according to claim 11 , wherein a first resistive TCO layer is deposited before step b) and a second resistive TCO layer is deposited after step b).
15. The solar cell according to claim 1 , wherein the textured TCO layer contacts the substrate.
16. The solar cell according to claim 1 , wherein the absorber layer extends between the textured TCO layer and the resistive TCO layer.
17. The solar cell according to claim 1 , wherein the absorber layer is in direct contact with the textured TCO layer and the resistive TCO layer.