Tunneling-junction solar cell with copper grid for concentrated photovoltaic application
One embodiment of the present invention provides a photovoltaic module. The photovoltaic module includes an optical concentrator and a tunneling-junction solar cell. The tunneling-junction solar cell includes a base layer, a quantum-tunneling-barrier (QTB) layer situated above the base layer, an emitter layer, a front-side electrode, and a back-side electrode.
1. A solar cell, comprising:
a crystalline silicon base layer;
a first dielectric quantum-tunneling-barrier layer in direct contact with a first side of the base layer;
a first doped silicon layer having a band gap greater than a band gap of the base layer and positioned adjacent to the first dielectric quantum-tunneling-barrier layer;
a first electrode electrically coupled to the first doped silicon layer;
a second dielectric quantum-tunneling-barrier layer in direct contact with a second side of the base layer;
a second doped silicon layer having a band gap greater than the band gap of the base layer and positioned adjacent to the second dielectric quantum-tunneling-barrier layer; and
a second electrode electrically coupled to the second doped silicon layer.
2. The solar cell of claim 1 , wherein the first and second quantum-tunneling-barrier layers comprise at least one of:
silicon oxide (SiO x );
hydrogenated SiO x ;
silicon nitride (SiN x );
hydrogenated SiN x ;
aluminum oxide (AlO x );
silicon oxynitride (SiON); and
hydrogenated SiON.
3. The solar cell of claim 1 , wherein the first and second doped silicon layers comprise at least one of:
amorphous silicon;
nanocystalline silicon;
protocrystalline silicon; and
amorphous silicon carbide.
4. The solar cell of claim 1 , wherein the first electrode and second electrode each include a metal grid, which comprises Cu.
5. The solar cell of claim 4 , wherein the metal grid is formed using a plating technique; and
wherein the metal grid further comprises a barrier layer between Cu and the rest of the solar cell.
6. The solar cell of claim 1 , wherein at least one of the first and second electrodes includes a metal grid line having a curved surface, thereby allowing light incident upon the curved surface to be reflected toward the solar cell.
7. The solar cell of claim 1 , further comprising:
a first transparent conductive oxide layer positioned between the first doped silicon layer and the first electrode; and
a second transparent conductive oxide layer positioned between the second doped silicon layer and the second electrode.
8. The solar cell of claim 1 , wherein the crystalline silicon base layer is n-type doped;
wherein the first doped silicon layer is n-type doped and functions as a surface field layer; and
wherein the second doped silicon layer is p-type doped and functions as an emitter layer.
9. The solar cell of claim 1 , wherein the first side of the crystalline silicon base layer is configured to face the sun.
10. A photovoltaic module, comprising:
an optical concentrator; and
a solar cell, which comprises:
a crystalline silicon base layer;
a first dielectric quantum-tunneling-barrier layer in direct contact with a first side of the base layer;
a first doped silicon layer having a band gap greater than a band gap of the base layer and positioned adjacent to the first dielectric quantum-tunneling-barrier layer;
a first electrode electrically coupled to the first doped silicon layer;
a second dielectric quantum-tunneling-barrier layer in direct contact with a second side of the base layer;
a second doped silicon layer having a band gap greater than the band gap of the base layer and positioned adjacent to the second dielectric quantum-tunneling-barrier layer; and
a second electrode electrically coupled to the second doped silicon layer.