Solar cell element and method for manufacturing same
View Patent ↗A solar cell element having a transparent substrate body, a Na x Ag 1-x , layer, a ZnO layer, a transparent conductive layer, and a photoelectric conversion layer including an n-type semiconductor layer and a p-type semiconductor layer. The transparent substrate body, the Na x Ag 1-x layer, the ZnO layer, the transparent conductive layer, and the photoelectric conversion layer are stacked in this order, x represents a value of not less than 0.001 and not more than 0.02, the Na x Ag 1-x layer has a thickness of 2-15.2 nanometers, and the ZnO layer has an arithmetical mean roughness of not less than 20-750 nanometers. The ZnO layer is composed of a plurality of ZnO columnar crystal grain, each ZnO columnar crystal grain has a longitudinal direction along a normal line direction of the transparent substrate body, and each ZnO columnar crystal grain has a R2/R1 ratio of 1.1-1.6.
1. A method for generating an electric power using a solar cell element, the method comprising steps of:
(a) preparing a solar cell element comprising:
a transparent substrate body;
a Na x Ag 1-x layer;
a ZnO layer;
a transparent conductive layer;
a photoelectric conversion layer including an n-type semiconductor layer and a p-type semiconductor layer;
an n-side electrode; and
a p-side electrode; wherein
the transparent substrate body, the Na x Ag 1-x layer 22 , the ZnO layer, the transparent conductive layer, and the photoelectric conversion layer are stacked in this order;
the n-side electrode is electrically connected to the n-type semiconductor layer;
the p-side electrode is electrically connected to the p-type semiconductor layer;
x represents a value of not less than 0.001 and not more than 0.02;
the Na x Ag 1-x layer has a thickness of not less than 2 nanometers and not more than 15.2 nanometers;
the ZnO layer has an arithmetic mean roughness of not less than 20 nanometers and not more than 750 nanometers;
the ZnO layer is composed of a plurality of ZnO columnar crystal grains grown on the surface of the Na x Ag 1-x layer;
each ZnO columnar crystal grain has a longitudinal direction along a line normal to the transparent substrate body;
each ZnO columnar crystal grain has a width which increases from the Na x Ag 1-x layer toward the transparent conductive layer;
the width of each ZnO columnar crystal grain is perpendicular to the longitudinal direction; and
each ZnO columnar crystal grain has a R2/R1 ratio of not less than 1.1 and not more than 1.6;
where R1 represents a width of a first end of the ZnO columnar crystal grain, the first end being in contact with the surface of the Na x Ag 1-x layer; and
R2 represents a width of a second end of the ZnO columnar crystal grain, wherein the second end is opposite to the first end; and
(b) irradiating the photoelectric conversion layer with light through the transparent substrate body, the Na x Ag 1-x layer, the ZnO layer, and the transparent conductive layer, so as to generate electric power between the n-side electrode and the p-side electrode.
2. The method according to claim 1 , wherein
the solar cell element further comprises a reverse surface electrode layer; and
the photoelectric conversion layer is interposed between the reverse surface electrode layer and the transparent conductive layer.
3. The method according to claim 2 , wherein
the n-type semiconductor layer is interposed between the transparent conductive layer and the p-type semiconductor layer; and
the p-type semiconductor layer is interposed between the n-type semiconductor layer and the reverse surface electrode layer.
4. The method according to claim 3 , wherein
the n-side electrode is formed on the transparent conductive layer; and
the p-side electrode is formed on the reverse surface electrode layer.
5. The method according to claim 1 , wherein
the ZnO layer has a volume resistivity of not less than 1×10 −3 Ω·cm.
6. The method according to claim 1 , wherein
the transparent conductive layer has a volume resistivity of less than 1×10 −3 Ω·cm.
7. The method according to claim 1 , wherein
the ZnO layer has a volume resistivity of not less than 1×10 −3 Ω·cm; and
the transparent conductive layer is formed of ZnO having a volume resistivity of less than 1×10 −3 Ω·cm.
8. The method according to claim 1 , wherein
the light is sunlight.
9. A solar cell element comprising:
a transparent substrate body;
a Na x Ag 1-x layer;
a ZnO layer;
a transparent conductive layer;
a photoelectric conversion layer including an n-type semiconductor layer and a p-type semiconductor layer;
an n-side electrode; and
a p-side electrode; wherein
the transparent substrate body, the Na x Ag 1-x layer, the ZnO layer, the transparent conductive layer, and the photoelectric conversion layer are stacked in this order;
the n-side electrode is electrically connected to the n-type semiconductor layer;
the p-side electrode is electrically connected to the p-type semiconductor layer;
x represents a value of not less than 0.001 and not more than 0.02;
the Na x Ag 1-x layer has a thickness of not less than 2 nanometers and not more than 15.2 nanometers;
the ZnO layer has an arithmetic mean roughness of not less than 20 nanometers and not more than 750 nanometers;
the ZnO layer is composed of a plurality of ZnO columnar crystal grains grown on the surface of the Na x Ag 1-x layer;
each ZnO columnar crystal grain has a longitudinal direction along a line normal to the transparent substrate body;
each ZnO columnar crystal grain has a width which increases from the Na x Ag 1-x layer toward the transparent conductive layer;
the width of each ZnO columnar crystal grain is perpendicular to the longitudinal direction; and
each ZnO columnar crystal grain has a R2/R1 ratio of not less than 1.1 and not more than 1.6;
where R1 represents a width of a first end of the ZnO columnar crystal grain, the first end being in contact with the surface of the Na x Ag 1-x layer; and
R2 represents a width of a second end of the ZnO columnar crystal grain, wherein the second end is opposite to the first end.
10. The solar cell element according to claim 9 , wherein
the solar cell element further comprises a reverse surface electrode layer; and
the photoelectric conversion layer is interposed between the reverse surface electrode layer and the transparent conductive layer.
11. The solar cell element according to claim 10 , wherein
the n-type semiconductor layer is interposed between the transparent conductive layer and the p-type semiconductor layer; and
the p-type semiconductor layer is interposed between the n-type semiconductor layer and the reverse surface electrode layer.
12. The solar cell element according to claim 11 , wherein
the n-side electrode is formed on the transparent conductive layer; and
the p-side electrode is formed on the reverse surface electrode layer.
13. The solar cell element according to claim 9 , wherein
the ZnO layer has a volume resistivity of not less than 1×10 −3 Ω·cm.
14. The solar cell element according to claim 9 , wherein
the transparent conductive layer has a volume resistivity of less than 1×10 −3 Ω·cm.
15. The solar cell element according to claim 9 , wherein
the ZnO layer has a volume resistivity of not less than 1×10 −3 Ω·cm; and
the transparent conductive layer is formed of ZnO having a volume resistivity of less than 1×10 −3 Ω·cm.