Organic double-heterostructure photovoltaic cells having reciprocal-carrier exciton blocking layer

Abstract

A photosensitive cell includes an anode and a cathode; a donor-type organic material and an acceptor-type organic material forming a donor-acceptor junction connected between the anode and the cathode; and an exciton blocking layer connected between the acceptor-type organic material of the donor-acceptor junction and the cathode, the blocking layer consisting essentially of a material that has a hole mobility of at least 10 −7 cm 2 /V-sec or higher, where a HOMO of the blocking layer is higher than or equal to a HOMO of the acceptor-type material.

1 . A photosensitive cell comprising: 
 an anode and a cathode;    a donor-type organic material and an acceptor-type organic material forming a donor-acceptor junction connected between the anode and the cathode; and    an exciton blocking layer connected between the acceptor-type organic material of the donor-acceptor junction and the cathode, the exciton blocking layer consisting essentially of a first material that has a hole mobility of at least 10 −7  cm 2  V-sec or higher,    wherein a HOMO of the exciton blocking layer is higher than or equal to a HOMO of the acceptor-type organic material.    
     
     
         2 . The photosensitive cell according to  claim 1 , wherein the hole mobility of the first material is at least 10 −6  cm 2 /V-sec or higher.  
     
     
         3 . The photosensitive cell according to  claim 1 , wherein a Fermi level of the cathode is no more than 1 eV higher than the HOMO of the exciton blocking layer.  
     
     
         4 . The photosensitive cell according to  claim 3 , wherein the Fermi level of the cathode is not higher than the HOMO of the exciton blocking layer.  
     
     
         5 . The photosensitive cell according to  claim 1 , wherein the HOMO of the exciton blocking layer is no more than 1 eV lower than a LUMO of the acceptor-type organic material.  
     
     
         6 . The photosensitive cell according to  claim 1 , wherein the exciton blocking layer comprises tris(acetylacetonato) ruthenium(III).  
     
     
         7 . The photosensitive cell according to  claim 1 , wherein the first material has the hole mobility of at least 10 −7  cm 2 /V-sec or higher in the absence of damage-mediated charge transport.  
     
     
         8 . The photosensitive cell according to  claim 7 , wherein the first material has the hole mobility of at least 10 −7  cm 2 /V-sec or higher in the absence of dopants and impurities.  
     
     
         9 . A photosensitive cell comprising: 
 an anode and a cathode;    a donor-type organic material and an acceptor-type organic material forming a donor-acceptor junction connected between the anode and the cathode; and    an exciton blocking layer connected between the acceptor-type organic material of the donor-acceptor junction and the cathode, wherein a Fermi level of the cathode is no more than 1 eV higher than a HOMO of the exciton blocking layer.    
     
     
         10 . The photosensitive cell according to  claim 9 , wherein the Fermi level of the cathode is not higher than the HOMO of the exciton blocking layer.  
     
     
         11 . The photosensitive cell according to  claim 9 , wherein the HOMO of the exciton blocking layer is higher than or equal to a HOMO of the acceptor-type organic material.  
     
     
         12 . The photosensitive cell according to  claim 9 , wherein the HOMO of the exciton blocking layer is no more than 1 eV lower than a LUMO of the acceptor-type organic material.  
     
     
         13 . The photosensitive cell according to  claim 9 , wherein the exciton blocking layer comprises tris(acetylacetonato) ruthenium(III).  
     
     
         14 . The photosensitive cell according to  claim 9 , the blocking layer consisting essentially of a first material that has a hole mobility of at least 10 −   7  cm 2 /V-sec or higher.  
     
     
         15 . The photosensitive cell according to  claim 14 , wherein the hole mobility of the first material is at least 10 −6  cm 2 /V-sec or higher.  
     
     
         16 . The photosensitive cell according to  claim 14 , wherein the first material has the hole mobility of at least 10 −7  cm 2 /V-sec or higher in the absence of damage-mediated charge transport.  
     
     
         17 . The photosensitive cell according to  claim 16 , wherein the first material has the hole mobility of at least 10 −7  cm 2 /V-sec or higher in the absence of dopants and impurities.