Transparent substrate provided with an electrode
Transparent substrate, especially made of glass, associated with an electrode, especially one suitable for solar cells, characterized in that the electrode comprises a first transparent electrically conducting layer composed of an undoped mineral oxide, said first layer being coated with a second transparent electrically conducting layer composed of the same mineral oxide, said mineral oxide however being doped.
1. A transparent substrate, associated with an electrode, the electrode comprising:
a first transparent electrically conducting layer composed of an undoped mineral oxide, the first layer being coated with a second transparent electrically conducting layer composed of the same mineral oxide, the mineral oxide being doped,
wherein the electrode possesses a factor, based on haze (H(%)) and light transmission(T L ), which is defined by the following equations:
0.25 ×H (%)+ T L >86.5 0 <H (%)<10
0.4 ×H (%)+ T L >88 H (%)≧10.
2. The substrate as claimed in claim 1 , wherein the electrode possesses a haze of between 5% and 25%.
3. The substrate as claimed in claim 1 , wherein a product of a light absorption of the electrode multiplied by an electrical surface resistance of the electrode is less than 0.6Ω/□.
4. The substrate as claimed in claim 1 , wherein a thickness of the first layer based on an undoped mineral oxide is between 150 and 900 nm.
5. The substrate as claimed in claim 1 , wherein the first layer is based on tin oxide (SnO 2 ) and the second layer is based on fluorine-doped tin oxide (SnO 2 :F).
6. The substrate as claimed in claim 1 , wherein the first layer is based on zinc oxide (ZnO) and the second layer is based on aluminum-doped zinc oxide (ZnO:Al).
7. The substrate as claimed in claim 1 , further comprising at least one barrier layer, acting as a barrier to alkali metals, inserted between the substrate and the electrode.
8. The substrate as claimed in claim 7 , wherein the barrier layer is based on a dielectric, chosen from at least one of the following compounds:
silicon nitride or oxinitride, silicon oxide or oxicarbide.
9. The substrate as claimed in claim 7 , wherein the barrier layer forms part of a multilayer coating with an optical function, including at least two layers of dielectrics having different refractive indices.
10. The substrate as claimed in claim 1 , wherein the doped and/or undoped mineral oxide are/is deposited at a temperature above 600° C., by CVD.
11. The substrate as claimed in claim 1 , further comprising at least one overlayer based on zinc oxide, the overlayer being deposited on the second layer which is based on fluorine-doped tin oxide (SnO 2 :F).
12. The substrate as claimed in claim 1 , wherein the substrate is an extra-clear glass.
13. The substrate as claimed in claim 1 , wherein one of faces of the substrate is coated with a multilayer that provides a functionality of antireflection or hydrophobic or photocatalytic type.
14. A solar cell, comprising the substrate as claimed in claim 1 .
15. The substrate as claimed in claim 2 , wherein the electrode possesses a haze of between 10% and 20%.