Multi-junction photovoltaic cells

Abstract

A photovoltaic device including a photovoltaic cell and method of use is disclosed. The photovoltaic cell includes at least a first photovoltaic layer and a second photovoltaic layer arranged in a stack. The first photovoltaic layer has a first thickness and receives light at its top surface. A second photovoltaic layer has a second thickness and is disposed beneath the first photovoltaic layer and receives light passing through the first photovoltaic layer. The first thickness and the second thickness are selected so that a first light absorption at the first photovoltaic layer is equal to a second light absorption at the second photovoltaic layer. The photovoltaic cell is irradiated at its top surface with monochromatic light to generate a current.

1 . A photovoltaic device, comprising:
 a photovoltaic cell, including:
 a first photovoltaic layer that receives light at a top surface of the first photovoltaic layer, the first photovoltaic layer having a first thickness; and 
 a second photovoltaic layer disposed beneath the first photovoltaic layer that receives light passing through the first photovoltaic layer, the second photovoltaic layer having a second thickness; 
 wherein the first thickness and the second thickness are selected so that a first light absorption at the first photovoltaic layer is equal to a second light absorption at the second photovoltaic layer. 
   
     
     
         2 . The photovoltaic device of  claim 1 , further comprising a tunnel layer sandwiched between the first photovoltaic layer and the second photovoltaic layer. 
     
     
         3 . The photovoltaic device of  claim 1 , wherein the light is monochromatic and a material of the first and second photovoltaic layers generates a current when irradiated at a wavelength of the monochromatic light. 
     
     
         4 . The photovoltaic device of  claim 1 , wherein the first photovoltaic layer is electrically connected in series with the second photovoltaic layer. 
     
     
         5 . The photovoltaic device of  claim 1 , further comprising a processor layer coupled to the photovoltaic cell, wherein the processor layer operates using a current generated by the photovoltaic cell. 
     
     
         6 . The photovoltaic device of  claim 5 , further comprising a memory layer coupled to the processor layer. 
     
     
         7 . The photovoltaic device of  claim 5 , further comprising a light emitting device (LED) coupled to the processor layer, wherein the processor controls operation of the LED and the LED operates using a current generated by the photovoltaic cell. 
     
     
         8 . A photovoltaic device, comprising:
 a photovoltaic cell including a plurality of photovoltaic layers arranged in a stack, wherein a thickness of each of the plurality of photovoltaic layer is selected so that an amount of light absorption absorbed at each of the plurality of photovoltaic layer is the same.   
     
     
         9 . The photovoltaic device of  claim 8 , further comprising a tunnel layer sandwiched between each of the plurality of photovoltaic layer. 
     
     
         10 . The photovoltaic device of  claim 8 , wherein a voltage across each of the plurality of photovoltaic layers when irradiated by a monochromatic light is substantially the same. 
     
     
         11 . The photovoltaic device of  claim 8 , wherein the light intensity at a bottom surface of the photovoltaic cell is substantially zero. 
     
     
         12 . The photovoltaic device of  claim 8 , further comprising a processor layer coupled to the photovoltaic cell, wherein the processor layer operates using a current generated at the photovoltaic cell. 
     
     
         13 . The photovoltaic device of  claim 12 , further comprising a memory layer coupled to the processor layer. 
     
     
         14 . The photovoltaic device of  claim 12 , further comprising a light emitting device (LED) coupled to the processor layer, wherein the processor controls operation of the LED layer to generate light and the LED operates using a current generated by the photovoltaic cell. 
     
     
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