Method and structure for thin film tandem photovoltaic cell

Abstract

A tandem photovoltaic cell. The tandem photovoltaic cell includes a bifacial top cell and a bottom cell. The top bifacial cell includes a top first transparent conductive oxide material. A top window material underlies the top first transparent conductive oxide material. A first interface region is disposed between the top window material and the top first transparent conductive oxide material. The first interface region is substantially free from one or more entities from the top first transparent conductive oxide material diffused into the top window material. A top absorber material comprising a copper species, an indium species, and a sulfur species underlies the top window material. A top second transparent conductive oxide material underlies the top absorber material. A second interface region is disposed between the top second transparent conductive oxide material and the top absorber material. The bottom cell includes a bottom first transparent conductive oxide material. A bottom window material underlies the first bottom transparent conductive oxide material. A bottom absorber material underlies the bottom window material. A bottom electrode material underlies the bottom absorber material. The tandem photovoltaic cell further includes a coupling material free from a parasitic junction between the top cell and the bottom cell.

1 . A tandem photovoltaic cell comprising:
 a bifacial top cell comprising:
 a top first transparent conductive oxide material; 
 a top window material underlying the top first transparent conductive oxide material; 
 a first interface region between the top window material and the top first transparent conductive oxide material, the first interface region being substantially free from one or more entities from the top first transparent conductive oxide material being diffused into the top window material; 
 a top absorber material underlying the top window material, the top absorber material comprising a copper species, an indium species, and a sulfur species; 
 a top second transparent conductive oxide material underlying the top absorber material; 
 a second interface region between the top second transparent conductive oxide material and the top absorber material, the second interface region being substantially free from one or more entities from the top first transparent conductive oxide material being diffused into the top absorber material; and 
   a bottom cell comprising:
 a bottom first transparent conductive oxide material; 
 a bottom window material underlying the first bottom transparent conductive oxide material; 
 a bottom absorber material underlying the bottom window material; and 
 a bottom electrode material underlying the bottom absorber material; 
   a coupling material between the top cell and the bottom cell, the coupling material being free from a parasitic junction between the top cell and the bottom cell.   
     
     
         2 . The photovoltaic cell of  claim 1  wherein the first transparent conductive oxide material is selected from a group consisting of: indium tin oxide (ITO), aluminum doped zinc oxide (ZnO:Al), or Fluorine doped tin oxide (SnO 2 :F). 
     
     
         3 . The photovoltaic cell of  claim 1  wherein the top window material is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO). 
     
     
         4 . The photovoltaic cell of  claim 1  wherein the top absorber material is selected from: copper indium disulfide (CIS), copper indium aluminum disulfide, copper indium gallium disulfide (CIGS), or (Ag,Cu)(In,Ga)S2. 
     
     
         5 . The photovoltaic cell of  claim 1  wherein the top second transparent conductive oxide is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO) 
     
     
         6 . The photovoltaic cell of  claim 1  wherein the bottom first transparent conductive oxide is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO) 
     
     
         7 . The photovoltaic cell of  claim 1  wherein the bottom window material is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO). 
     
     
         8 . The photovoltaic cell of  claim 1  wherein the bottom electrode material is selected from a transparent conductive oxide material or a metal material. 
     
     
         9 . The photovoltaic cell of  claim 1  wherein the bottom absorber material is selected from: a copper indium disulfide thin film material, copper indium aluminum disulfide thin film material, or a copper indium gallium disulfide material. 
     
     
         10 . The photovoltaic cell of  claim 1  wherein the bottom absorber material is selected from: Cu 2 SnS 3 ; Cu(In,Ga)Se 2 ; CuInSe 2 ; or FeSi 2 . 
     
     
         11 . A tandem photovoltaic cell comprising:
 a bifacial top cell comprising:
 a top first TCO material; 
 a top window material underlying the top first TCO material; 
 a top absorber material underlying the top window material, the top absorber material comprising a copper species, an indium species, and a sulfur species; 
 a top second TCO material underlying the top absorber material; and 
   a bottom cell comprising:
 a bottom first TCO material; 
 a bottom window material underlying the first bottom TCO material; 
 a bottom absorber material underlying the bottom window material; and 
 a bottom electrode material underlying the bottom absorber material; 
   a coupling material between the top cell and the bottom cell, the coupling material being free from a parasitic junction between the top cell and the bottom cell.   
     
     
         12 . The photovoltaic cell of  claim 11  wherein the first transparent conductive oxide material is selected from a group consisting of: indium tin oxide (ITO), aluminum doped zinc oxide (ZnO:Al), or Fluorine doped tin oxide (SnO 2 :F). 
     
     
         13 . The photovoltaic cell of  claim 11  wherein the top window material is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO). 
     
     
         14 . The photovoltaic cell of  claim 11  wherein the top absorber material is selected from: copper indium disulfide (CIS), copper indium aluminum disulfide, copper indium gallium disulfide (CIGS), or (Ag,Cu)(In,Ga)S2. 
     
     
         15 . The photovoltaic cell of  claim 11  wherein the top second transparent conductive oxide is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO) 
     
     
         16 . The photovoltaic cell of  claim 11  wherein the bottom first transparent conductive oxide is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO) 
     
     
         17 . The photovoltaic cell of  claim 11  wherein the bottom window material is selected from: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc oxide (ZnO), or zinc magnesium oxide (ZnMgO). 
     
     
         18 . The photovoltaic cell of  claim 11  wherein the bottom absorber material is selected from: a copper indium disulfide thin film material, copper indium aluminum disulfide thin film material, or a copper indium gallium disulfide material. 
     
     
         19 . The photovoltaic cell of  claim 11  wherein the bottom absorber material is selected from: Cu 2 SnS 3 ; Cu(In,Ga)Se 2 ; CuInSe 2 ; or FeSi 2 . 
     
     
         20 . A method for fabricating a tandem photovoltaic cell, comprising:
 forming a bifacial top cell, comprising:
 providing a top first transparent conductive oxide material; 
 forming a top window material underlying the top first transparent conductive oxide material; 
 forming a first interface region between the top window material and the top first transparent conductive oxide material, the first interface region being substantially free from one or more entities from the top first transparent conductive oxide material being diffused into the top window material; 
 forming a top absorber material underlying the top window material, the top absorber material comprising a copper species, an indium species, and a sulfur species; 
 forming a top second transparent conductive oxide material underlying the top absorber material; 
 forming a second interface region between the top second transparent conductive oxide material and the top absorber material, the second interface region being substantially free from one or more entities from the top first transparent conductive oxide material being diffused into the top absorber material; and 
   forming a bottom cell, comprising:
 forming a bottom first transparent conductive oxide material; 
 forming a bottom window material underlying the first bottom transparent conductive oxide material; 
 forming a bottom absorber material underlying the bottom window material; and 
 forming a bottom electrode material underlying the bottom absorber material; 
   providing a coupling material disposed between the bifacial top cell and the bottom cell, the coupling material being free from a parasitic junction between the bifacial top cell and the bottom cell.