Solar cell
A solar cell comprising a crystalline silicon substrate, a semiconductor layer arranged on a back surface of the substrate which is configured not to face a radiative source, when the solar cell is in use, and a transparent-conductive region arranged on a surface of the semiconductor layer, wherein the transparent conductive region comprises: a first layer having a first work function; and a second layer having a second work function and being interposed between the first layer and the semiconductor layer; wherein the second work function of the second layer is greater than the first work function of the first layer.
1 . A solar cell comprising:
a substrate comprised of crystalline silicon;
a first semiconductor layer arranged on a back surface of the substrate;
a second semiconductor layer arranged on a front surface of the substrate which is configured to face a radiative source, when the solar cell is in use;
a first transparent-conductive region arranged on a surface of the first semiconductor layer, wherein the first transparent conductive region comprises:
a first rear layer having a first rear work function; and
a second rear layer having a second rear work function and being interposed between the first rear layer and the first semiconductor layer;
wherein the second rear work function of the second rear layer is greater than the first rear work function of the first rear layer; and
a second transparent-conductive region being arranged on a surface of the second semiconductor layer, wherein the second transparent-conductive region comprises:
a first front layer having a first front work function; and
a second front layer having a second front work function and being interposed between the first front layer and the second semiconductor layer; and
a third front layer being interposed between the second front layer and the second semiconductor layer and arranged directly on the second semiconductor layer;
wherein the second front work function of the second front layer is greater than the first front work function of the first front layer;
wherein the third front layer is configured with a third front work function which is greater than the second front work function of the second front layer; and
wherein the second semiconductor layer comprises amorphous silicon (a-Si).
2 . The solar cell according to claim 1 , wherein the first semiconductor layer is further configured with a positive conductivity type.
3 . The solar cell according to claim 1 , wherein the second rear work function of the second rear layer is configured to be less than the work function of the first semiconductor layer.
4 . The solar cell according to claim 1 , wherein a difference between the work function of the first semiconductor layer and the second rear work function of the second rear layer is less than the difference between the work function of the first semiconductor layer and the first rear work function of the first rear layer.
5 . The solar cell according to claim 1 , wherein the second rear work function of the second rear layer is configured to be up to 15% greater than the first rear work function of the first rear layer.
6 . The solar cell according to claim 1 , wherein the first transparent-conductive region comprises a third rear layer being interposed between the second rear layer and the first semiconductor layer, wherein the third rear layer is configured with a third rear work function which is greater than the second rear work function of the second rear layer.
7 . The solar cell according to claim 6 , wherein the third rear layer is arranged directly on the first semiconductor layer.
8 . The solar cell according to claim 7 , wherein the third rear work function of the third rear layer is configured to be up to 15% greater than the second rear work function of the second rear layer.
9 . The solar cell according to claim 7 , wherein the third rear work function of the third rear layer is configured to be less than the work function of the first semiconductor layer.
10 . The solar cell according to claim 1 , wherein the work function of a layer of the first transparent-conductive region that is furthest from the substrate is greater than 3.5 eV and less than 4.5 eV, and/or the work function of a layer of the first transparent-conductive region that is closest to the substrate is greater than 5.0 eV and less than 6.0 eV.
11 . The solar cell according to claim 1 , wherein the work function of the first semiconductor layer is greater than 5.0 eV and less than 6.0 eV.
12 . The solar cell according to claim 6 , wherein the first transparent-conductive region has a thickness of less than 500 nm, and wherein each of the layers of the first transparent-conductive region has a thickness of at least 20 nm and no more than 50 nm.
13 . The solar cell according to claim 6 , wherein at least one of the layers of the first transparent-conductive region is formed of a metal oxide material, and the first semiconductor layer is comprised of amorphous silicon (a-Si).
14 . The solar cell according to claim 1 , wherein the second semiconductor layer is configured with a negative conductivity type.
15 . The solar cell according to claim 1 , wherein the second semiconductor layer defines an accumulator layer.
16 . The solar cell according to claim 1 , wherein at least one of the layers of the second transparent-conductive region is formed of a metal oxide material.
17 . A solar module comprising a plurality of solar cells according to claim 1 , wherein the plurality of solar cells are electrically coupled together.
18 . The solar cell according to claim 1 , wherein the second rear work function of the second rear layer is configured to be up to 10% greater than the first rear work function of the first rear layer.
19 . The solar cell according to claim 1 , wherein the second rear work function of the second rear layer is configured to be at least 10% and up to 15% greater than the first rear work function of the first rear layer.
20 . The solar cell according to claim 6 , wherein the third rear work function of the third rear layer is up to 10% greater than the second rear work function of the second rear layer.