Flexible Monocrystalline Thin Silicon Cell

Abstract

A device, system, and method for solar cell construction and layer transfer are disclosed herein. An exemplary method of solar cell construction involves providing a silicon donor substrate. A porous layer is formed on the donor substrate. A first portion of a solar cell is constructed on the porous layer of the donor substrate. The solar cell and donor substrate are bonded to a flexible substrate. The flexible substrate and the first portion of a solar cell are then separated from the donor substrate at the porous layer. A second portion of a solar cell may then be constructed on the first portion of a solar cell providing a single completed solar cell.

The invention claimed is: 
     
         1 . A low porosity layer silicon donor substrate;
 a n+ doped epitiaxial silicon film on the porous layer;   a n− doped epitiaxial silicon film on the n+ doped epitiaxial silicon film;   a passivation layer with openings on top of the n− doped epitiaxial silicon film;   an aluminum layer with emitters within the openings; and   a flexible substrate wherein a metal coating bonds the flexible substrate to the aluminum layer.   
     
     
         2 . The solar cell device of  claim 1 , wherein the flexible substrate is poly-oxydiphenylene-pyromellitimide. 
     
     
         3 . The solar cell device of  claim 1 , wherein the flexible substrate is borosilicate glass.4. A method of solar cell construction, the method comprising:
 providing silicon donor substrate;   forming porous layer on the silicon donor substrate;   constructing a first portion of a solar cell on the porous layer of the silicon donor substrate;   plating a metal support film on a surface of the first portion of the solar cell; and   separating the metal support film and the first portion of the solar cell from the silicon donor substrate at the porous layer.   
     
     
         5 . The method of claim  4 , wherein the metal support film is a composite plating. 
     
     
         6 . The method of claim  4 , wherein the metal support film is a composite plating and comprises particles of amorphous silica or graphite fibers. 
     
     
         7 . The method of claim  4 , wherein the metal support film is a composite plating having a coefficient of thermal expansion less than 5 ppm/° K. 
     
     
         8 . The method of claim  4 , wherein the metal support film is a composite of nickel with about 50 percent (by volume) silica particles. 
     
     
         9 . The method of claim  4 , wherein the metal support film is a composite plating having a coefficient of thermal expansion matching the silicon. 
     
     
         10 . The method of claim  4 , wherein the metal support film is a composite of copper with about 40 percent (by volume) graphite fibers. 
     
     
         11 . The method of claim  4 , wherein the metal support film has a thickness of about 50-500 microns 
     
     
         12 . The method of claim  4 , wherein the metal support film is a composite plating having a coefficient of thermal expansion based on the front side processing temperatures of the solar cell and a silicon thickness of the first portion of the solar cell. 
     
     
         13 . A method of solar cell construction, the method comprising:
 providing silicon donor substrate;   forming porous layer on the silicon donor substrate;   depositing the absorber layer on the porous layer;   constructing a first portion of a Heterojunction with Intrinsic Thin (HIT) solar cell on the absorber layer;   bonding the silicon donor substrate and the first portion of the HIT solar cell to a conductive carrier substrate with a solder or eutectic bond;   separating the conductive carrier substrate and the first portion of the HIT solar cell from the silicon donor substrate at the porous layer; and   constructing a second portion of the HIT solar cell on the porous layer of the conductive carrier substrate and the first portion of the HIT solar cell.