Organic Salts For High Voltage Organic And Transparent Solar Cells

Abstract

Photo-active devices including a substrate, a first electrode, an active layer including an organic salt or salt mixture that selectively or predominantly harvests light from the near infrared or infrared regions of the solar spectrum, and a second electrode. The devices are either visibly transparent or visibly opaque and can be utilized in single- or multi-junction devices.

What is claimed is: 
     
         1 . A photovoltaic device comprising:
 a first electrode;   a second electrode; and   an active layer comprising an organic semiconductor positioned between the first electrode and the second electrode,   wherein the photovoltaic device has an open circuit voltage that is within 30% of the excitonic limit.   
     
     
         2 . The photovoltaic device according to  claim 1 , wherein the organic semiconductor selectively or predominantly absorbs light in at least one of the near infrared or infrared regions of the solar spectrum. 
     
     
         3 . The photovoltaic device according to  claim 1 , wherein the organic semiconductor is an organic salt. 
     
     
         4 . The photovoltaic device according to  claim 3 , wherein the organic salt absorbs light having a wavelength from about 675 nm to about 1600 nm. 
     
     
         5 . The photovoltaic device according to  claim 4 , wherein the photovoltaic device is visibly transparent. 
     
     
         6 . The photovoltaic device according to  claim 5 , having an average visible transparency, weighted by the photopic response of an eye, of about 50% or more for specular transmission. 
     
     
         7 . The photovoltaic device according to  claim 3 , wherein the organic salt comprises a counterion selected from the group consisting of halides, aryl borates, carboranes, phosphates, fluoroantimonates, fluoroborates, derivatives thereof, and combinations thereof. 
     
     
         8 . The photovoltaic device according to  claim 7 , wherein the organic salt comprises a polymethine ion or a cyanine ion. 
     
     
         9 . The photovoltaic device according to  claim 3 , wherein the active layer comprises a first organic salt and a second organic salt, wherein the first and second organic salts have a common cation, but different anions. 
     
     
         10 . The photovoltaic device according to  claim 1 , wherein the photovoltaic device is visibly opaque. 
     
     
         11 . The photovoltaic device according to  claim 1 , further comprising a complementary layer comprising an electron donor or an electron acceptor. 
     
     
         12 . The photovoltaic device according to  claim 1 , wherein the photovoltaic device is integrated in a multijunction device as a subcell. 
     
     
         13 . The photo-active device according to  claim 1 , wherein the open circuit voltage is within 20% of the excitonic limit. 
     
     
         14 . A photovoltaic device comprising:
 a first electrode;   a second electrode; and   an active layer positioned between the first electrode and the second electrode, the active layer comprising:
 a first organic salt having an ion and a first counterion; and 
 a second organic salt having the same ion as the first organic salt and a second counterion, the second counterion being different from the first counterion. 
   
     
     
         15 . The photovoltaic device according to  claim 14 , wherein the first and second organic salts selectively or predominantly absorb light in at least one of the near infrared or infrared regions of the solar spectrum, and wherein the photovoltaic device is visibly transparent, having an average visible transparency, weighted by the photopic response of an eye, of about 50% or more for specular transmission. 
     
     
         16 . The photovoltaic device according to  claim 14 , wherein the first and second counterions are independently selected from the group consisting of halides, aryl borates, carboranes, phosphates, fluoroantimonates, fluoroborates, derivatives thereof, and combinations thereof. 
     
     
         17 . The photovoltaic device according to  claim 16 , wherein at least one of the first or second counterions is not a fluorophosphate. 
     
     
         18 . The photovoltaic device according to  claim 14 , having an open circuit voltage that is within 30% of the excitonic limit. 
     
     
         19 . The photovoltaic device according to  claim 18 , wherein the open circuit voltage is within 20% of the excitonic limit. 
     
     
         20 . A method of manufacturing a photo-active device, the method comprising:
 disposing an active layer between a first electrode and a second electrode,   wherein the active layer comprises an organic salt comprising a counterion selected from the group consisting of halides, aryl borates, carboranes, phosphates, fluoroantimonates, fluoroborates, derivatives thereof, and combinations thereof, wherein the phosphates do not include fluorophosphates, and   wherein the active layer harvests light.