Solar cell element
View Patent ↗A solar cell element includes: a transparent body; a Li x Ag 1-x layer (0.001≦x≦0.05) having a thickness (2-15 nm); a ZnO layer having an arithmetical mean roughness (20-760 nm); a transparent conductive layer; and a photoelectric conversion layer including n-type and p-type layers, further includes n-side and p-side electrodes, the ZnO layer is composed of ZnO columnar crystal grains grown on the Li x Ag 1-x layer; each ZnO grain has a longitudinal direction along a normal line of the body, and has a width increasing from the Li x Ag 1-x layer toward the transparent conductive layer, and has a width which appears by cutting each ZnO grain along the normal line, and has a R2/R1 ratio (1.1-1.6); where R1 represents the width of one end of the ZnO grain, the one end being in contact with the surface of the Li x Ag 1-x layer; and R2 represents the width of the other end of the ZnO grain.
1. A method for generating an electric power using a solar cell element, the method comprising:
(a) preparing the solar cell element comprising:
a transparent substrate body;
a Li 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 Li 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 0.05;
the Li x Ag 1-x layer has a thickness of not less than 2 nanometers and not more than 15 nanometers;
the ZnO layer has a arithmetical mean roughness of not less than 20 nanometers and not less than 760 nanometers;
the ZnO layer is composed of a plurality of ZnO columnar crystal grains grown on the surface of the Li x Ag 1-x layer;
each ZnO columnar crystal grain has a longitudinal direction along a normal line direction of the transparent substrate body;
each ZnO columnar crystal grain has a width which increases from the Li x Ag 1-x layer toward the transparent conductive layer;
the width of each ZnO columnar crystal grain appears by cutting each ZnO columnar crystal grain along the normal line direction of the transparent substrate body; 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 the width of one end of the ZnO columnar crystal grain, the one end being in contact with the surface of the Li x Ag 1-x layer; and
R2 represents the width of the other end of the ZnO columnar crystal grain; and
(b) irradiating the photoelectric conversion layer with light through the transparent substrate body, the Li x Ag 1-x layer, the ZnO layer, and transparent conductive layer, so as to generate an electric power between the n-side electrode and the p-side electrode.
2. The method according to claim 1 , wherein the solar cell element 9 further comprises a reverse surface electrode layer; and
the photoelectric conversion layer is interposed between the n-type semiconductor layer and the reverse surface electrode layer.
3. The method according to claim 2 , wherein the n-type semiconductor layer 41 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,
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 Li 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 Li 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 0.05;
the Li x Ag 1-x layer has a thickness of not less than 2 nanometers and not more than 15 nanometers;
the ZnO layer has a arithmetical mean roughness of not less than 20 nanometers and not less than 760 nanometers;
the ZnO layer is composed of a plurality of ZnO columnar crystal grains grown on the surface of the Li x Ag 1-x layer;
each ZnO columnar crystal grain has a longitudinal direction along a normal line direction of the transparent substrate body;
each ZnO columnar crystal grain has a width which increases from the Li x Ag 1-x layer toward the transparent conductive layer;
the width of each ZnO columnar crystal grain appears by cutting each ZnO columnar crystal grain along the normal line direction of the transparent substrate body; 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 the width of one end of the ZnO columnar crystal grain, the one end being in contact with the surface of the Li x Ag 1-x layer; and
R2 represents the width of the other end of the ZnO columnar crystal grain.
10. The solar cell 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 n-type semiconductor layer and the reverse surface electrode layer.
11. The solar cell according to claim 9 , 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 according to claim 9 , 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 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 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 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.