Photovoltaics with interferometric ribbon masks

Abstract

An interferometric mask covering a reflective conductive ribbon that electrically interconnects a plurality of photovoltaic cells is disclosed. Such an interferometric mask may reduce reflections of incident light from the conductors. In various embodiments, the mask reduces reflections, so that a front and back electrode pattern appears black or similar in color to surrounding features of the device. In other embodiments, the mask may modulate reflections of light such that the electrode pattern matches a color in the visible spectrum.

1 . A ribbon for a photovoltaic device, comprising:
 an elongated conductor configured to electrically connect a plurality of photovoltaic cells, the conductor having a reflective surface;   an optical resonant cavity layer disposed on the reflective surface of the conductor; and   an absorber layer, wherein the absorber layer is disposed on the optical resonant cavity layer, and wherein the absorber layer includes a semitransparent thickness of a metallic or a semiconductor layer,   wherein the optical resonant cavity and the absorber layer are configured to interferometrically reduce reflections from the conductor to a percentage of reflectivity less than about 10 percent.   
     
     
         2 . The ribbon of  claim 1 , wherein the reflective surface is defined by a metallic reflective layer deposited over a ribbon conductive layer. 
     
     
         3 . The ribbon of  claim 2 , wherein the metallic reflective layer is disposed between the optical resonant cavity layer and the conductor. 
     
     
         4 . The ribbon of  claim 2 , wherein the reflective layer is disposed on one side of the ribbon conductive layer. 
     
     
         5 . The ribbon of  claim 2 , wherein the reflective surface is disposed on upper and lower sides of the ribbon conductive layer. 
     
     
         6 . The ribbon of  claim 1 , wherein the reflective surface is defined by a surface of a single conductive layer forming the conductor surface of the conductor. 
     
     
         7 . The ribbon of  claim 1 , wherein the optical resonant cavity and the absorber layer are disposed on one side of the conductor. 
     
     
         8 . The ribbon of  claim 1 , wherein the optical resonant cavity and the absorber layer are disposed on both sides of the conductor. 
     
     
         9 . The ribbon of  claim 8 , wherein the optical resonant cavity and the absorber layer surround the conductor. 
     
     
         10 . The ribbon of  claim 9 , wherein the optical resonant cavity layer and the absorber layer are made of a conductive material. 
     
     
         11 . The ribbon of  claim 1 , wherein the optical resonant cavity layer and the absorber layer are configured such that a color of light reflected from the conductor substantially matches a color of surrounding features on the photovoltaic device. 
     
     
         12 . The ribbon of  claim 11 , wherein the optical resonant cavity layer and the absorber layer are configured such that the color of light reflected from the conductor substantially matches a color in the visible spectrum. 
     
     
         13 . The ribbon of  claim 1 , wherein the light reflected from the conductor falls within the wavelengths associated with the visible spectrum. 
     
     
         14 . The ribbon of  claim 1 , wherein the optical resonant cavity layer and the absorber layer are configured such that little or no incident visible light is reflected from the conductor such that the ribbon appears black from a normal viewing angle. 
     
     
         15 . The ribbon of  claim 1 , wherein the optical resonant cavity layer and the absorber layer are configured such that the reflectivity in the visible range from the conductor is less than 5%. 
     
     
         16 . A photovoltaic device comprising:
 means for generating an electrical current from incident light on a side of said means;   means for aligning and interconnecting a plurality of electrical current cells with said electrical current generating means; and   means for reducing reflected light from said means for aligning and interconnecting to less than about 10 percent.   
     
     
         17 . The device of  claim 16 , wherein the means for generating an electrical current includes a photovoltaic cell. 
     
     
         18 . The device of  claim 16 , wherein the means for aligning and interconnecting includes an elongated conductor. 
     
     
         19 . The device of  claim 18 , wherein the means for reducing reflected light from said means for aligning and interconnecting includes interferometric mask layers disposed over the elongated conductor, wherein the interferometric mask layers includes an optical resonant cavity and an absorber layer. 
     
     
         20 . A method of making a ribbon conductor for a photovoltaic device, comprising:
 providing a conductive strip; and   coating the conductive strip with a plurality of layers, wherein the layers form an optical resonant cavity over the conductive strip and an optical absorber layer over the optical resonant cavity, to define an interferometric modulator mask, wherein the optical absorber layer includes a semitransparent thickness of a metallic or a semiconductor layer, and wherein the optical resonant cavity and the optical absorber layers are configured to reduce a percentage of reflectivity from the conductive strip to less than about 10 percent.   
     
     
         21 . The method of  claim 20 , wherein the conductive strip is coated on both sides. 
     
     
         22 . The method of  claim 20 , wherein the interferometric modulator mask is configured to interferometrically reduce visible reflectivity from the conductive strip to less than 10%. 
     
     
         23 . The method of  claim 20 , wherein the optical resonant cavity and absorber layer are formed with a conductive material. 
     
     
         24 . The method of  claim 23 , wherein the optical resonant cavity is formed with at least one of ITO and ZnO. 
     
     
         25 . The method of  claim 23 , wherein the absorber layer is formed from at least one of Mo, Cr, MoCr, and Ti. 
     
     
         26 . The method of  claim 20 , further including a reflective layer disposed between the optical resonant cavity and the conductive strip. 
     
     
         27 . The method of  claim 20 , wherein coating the conductive strip includes:
 providing a substrate having interferometric mask layers, wherein the interferometric mask layers include an optical resonant cavity and an absorber layer;   subsequently laminating the substrate having the interferometric mask layers onto the conductive strip; and   removing the substrate from the interferometric mask layers after lamination on the conductive strip.