Materials and structures for enhancing the performance of organic light emitting devices

Abstract

A device is provided, having an anode, a cathode, and a first organic layer disposed between the anode and the cathode. The first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode. A second organic layer is disposed between the first organic layer and the cathode. The second organic layer is in direct contact with the first organic layer. The second organic layer may comprise an aromatic hydrocarbon material, comprising an aromatic non-heterocyclic hydrocarbon core optionally substituted, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl, substituted aryl, substituted heteroaryl and heterocyclic groups. The second organic layer may comprise a material having a molecular dipole moment less than about 2.0 debyes, such that the device has an unmodified external quantum efficiency of at least about 3% and a lifetime of at least about 1000 hours at an initial luminance of about 100 to about 1000 cd/m 2 . The second organic layer may be in direct contact with the cathode, or there may be a separate organic layer between the second organic layer and the cathode.

1 . A device, comprising: 
 an anode;    a cathode;    a first organic layer disposed between the anode and the cathode, wherein the first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode; and    a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises an aromatic non-heterocyclic hydrocarbon material.    
     
     
         2 . The device of  claim 1 , wherein the aromatic hydrocarbon material has a molecular dipole moment of less than about 2.0 debyes.  
     
     
         3 . The device of  claim 2 , wherein the aromatic hydrocarbon material has a molecular dipole moment of zero.  
     
     
         4 . The device of  claim 1 , wherein the aromatic hydrocarbon material comprises a material having the structure:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 —R 5  each represent no substitution, mono-, di-, or tri- substitution, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl.  
 
     
     
         5 . The device of  claim 4 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
     
     
         6 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 6 —R 10  each represent no substitution, mono-, di-, or tri- substitution, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl, and substituted aryl.  
 
     
     
         7 . The device of  claim 6 , wherein the aromatic comprises a hydrocarbon material having the structure:  
       
         
           
           
               
               
           
         
       
     
     
         8 . The device of  claim 1 , wherein the second organic layer is in direct contact with the cathode.  
     
     
         9 . The device of  claim 1 , further comprising a third organic layer disposed between the second organic layer and the cathode.  
     
     
         10 . The device of  claim 1 , wherein the aromatic hydrocarbon material has a highest occupied molecular orbital that is not more than 0.81 eV less than the highest occupied molecular orbital of the hole transporting material in the first organic layer.  
     
     
         11 . The device of  claim 10 , wherein the aromatic hydrocarbon material has a molecular dipole moment less than about 2.0 debyes.  
     
     
         12 . A device, comprising: 
 an anode;    a cathode;    an first organic layer disposed between the anode and the cathode, wherein the first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode;    a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises an aromatic non-heterocyclic hydrocarbon material having a highest occupied molecular orbital that is at least 0.81 eV less than the highest occupied molecular orbital of the hole transporting material in the first organic layer.    
     
     
         13 . The device of  claim 12 , wherein the aromatic hydrocarbon material has a molecular dipole moment less than about 2.0 debyes.  
     
     
         14 . A device, comprising: 
 an anode;    a cathode;    an first organic layer disposed between the anode and the cathode, wherein the first organic layer is comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode;    a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises an aromatic non-heterocyclic hydrocarbon material, and wherein the device has an unmodified external quantum efficiency of at least about 3% and a lifetime of at least about 1000 hours at an initial luminance of about 100 to about 1000 cd/m 2 .    
     
     
         15 . The device of  claim 14 , wherein the device has an unmodified external quantum efficiency of at least about 5% and a lifetime of at least about 1000 hours at an initial luminance of about 100 to about 1000 cd/m 2 .  
     
     
         16 . The device of  claim 14 , wherein the aromatic hydrocarbon material has a molecular dipole moment less than about 2.0 debyes.  
     
     
         17 . The device of  claim 14 , wherein the aromatic hydrocarbon material has a zero molecular dipole moment.  
     
     
         18 . The device of  claim 14 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 1 —R 5  each represent no substitution, mono-, di-, or tri- substitution, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl, and substituted aryl.  
 
     
     
         19 . The device of  claim 18 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
     
     
         20 . The device of  claim 14 , wherein after 100 hours of operation at an initial luminance of 600 cd/m 2  at least about 90% of initial luminance is retained.  
     
     
         21 . The device of  claim 14 , wherein after 1000 hours of operation at an initial luminance of 1000 cd/m 2  at least about 70% of initial luminance is retained.  
     
     
         22 . The device of  claim 14 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 6 —R 10  each represent no substitution, mono-, di-, or tri- substitution, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl, and substituted aryl.  
 
     
     
         23 . The device of  claim 22 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
     
     
         24 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 11 —R 13  each represents no substitution, mono-, di-, or tri- substitution, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl, and substituted aryl.  
 
     
     
         25 . The device of  claim 24 , wherein R 11 , R 12 , and R 13  are each phenyl.  
     
     
         26 . The device of  claim 25 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
     
     
         27 . The device of  claim 24 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         28 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 14 , R 19 , and R 20 —R 25  each represents no substitution, mono-, di-, or tri- or tetra- substitution, and R 15 —R 18  each represent no substitution, mono-, di-, tri- substitution, and  
 each R substituent is the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl.  
 
     
     
         29 . The device of  claim 28 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         30 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure:  
       
         
           
           
               
               
           
         
       
       wherein 
 R 26  represents no substitution, mono-, di-, tri-, or tetra substitution, and wherein each R is the same or different substituent, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl, and  
 each R may be linked together to form cyclic substituents such as cycloalkyl or aromatic non-heterocyclic rings.  
 
     
     
         31 . The device of  claim 30 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         32 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
       wherein 
 R 27  and R 28  each represents no substitution, mono-, di-, tri-, or tetra substitution, and wherein R 27  and R 28  are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl, and  
 each R may be linked together to form cyclic substituents such as cycloalkyl or aromatic non-heterocyclic rings.  
 
     
     
         33 . The device of  claim 32 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         34 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
       wherein 
 R 29 —R 31  each represents no substitution, mono-, di-, or tri- substitution, and wherein R 29 —R 31  are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl, and  
 each R may be linked together to form cyclic substituents such as cycloalkyl or aromatic non-heterocyclic rings.  
 
     
     
         35 . The device of  claim 34 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         36 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
       wherein 
 R 32 —R 34  each represents no substitution, mono-, di-, or tri- substitution, and wherein R 32 —R 34  are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl, and  
 each R may be linked together to form cyclic substituents such as cycloalkyl or aromatic non-heterocyclic rings.  
 
     
     
         37 . The device of  claim 36 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         38 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
       wherein 
 R 35 —R 37  each represents no substitution, mono-, di-, or tri- substitution, and wherein R 35 —R 37  are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl, and  
 each R may be linked together to form cyclic substituents such as cycloalkyl or aromatic non-heterocyclic rings.  
 
     
     
         39 . The device of  claim 38 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         40 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
       wherein 
 R 38 —R 41  each represents no substitution, mono-, di-, or tri- substitution, and wherein R 38 —R 41  are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl, and  
 each R may be linked together to form cyclic substituents such as cycloalkyl or aromatic non-heterocyclic rings.  
 
     
     
         41 . The device of  claim 40 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         42 . The device of  claim 1 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
       wherein 
 R 42 —R 45  each represents no substitution, mono-, di-, or tri- substitution, and wherein R 42 —R 45  are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl and substituted aryl, and  
 each R may be linked together to form cyclic substituents such as cycloalkyl or aromatic non-heterocyclic rings.  
 
     
     
         43 . The device of  claim 42 , wherein the aromatic hydrocarbon material has the structure  
       
         
           
           
               
               
           
         
       
     
     
         44 . The device of  claim 1 , wherein the second organic layer is in direct contact with the cathode.  
     
     
         45 . A device, comprising: 
 an anode;    a cathode;    a first organic layer disposed between the anode and the cathode, wherein the first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode; and    a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises aromatic material selected from the group consisting of:                          wherein:    R 1 —R 10  each represent no substitution, mono-, di-, or tri- substitution, R 11 —R 13 , R 15 —R 18 , each represents no substitution, mono-, di-, or tri- substitution, and R 14 , R 19 , and R 20 —R 25  each represents no substitution, mono-, di-, or tri- or tetra- substitution, and    and wherein R 1 —R 25  are the same or different substituents, and each is selected from the group consisting of alkyl, alkenyl, aryl, heteroalkyl, substituted aryl, substituted heteroaryl and heterocyclic groups.    
     
     
         46 . The device of  claim 45 , wherein the aromatic material has a molecular dipole moment of less than about 2.0 debyes.  
     
     
         47 . The device of  claim 46 , wherein the aromatic material has a molecular dipole moment of zero.  
     
     
         48 . The device of  claim 45 , wherein the aromatic material includes only C and H atoms.  
     
     
         49 . A device, comprising: 
 an anode;    a cathode;    a first organic layer disposed between the anode and the cathode, wherein the first organic layer comprises a material that produces phosphorescent emission when a voltage is applied between the anode and the cathode; and    a second organic layer disposed between the first organic layer and the cathode, wherein the second organic layer is in direct contact with the first organic layer, and wherein the second organic layer comprises an aromatic material wherein the aromatic material includes a core comprising at least 3 phenyl rings, wherein each phenyl ring in the core is connected to every other phenyl ring in the core either directly, or by a chain of phenyl rings that are either fused or attached by a single C—C bond.    
     
     
         50 . The device of  claim 49 , wherein the aromatic material includes a core comprising at least  6  phenyl rings.  
     
     
         51 . A compound, having the structure:  
       
         
           
           
               
               
           
         
       
       wherein: 
 R 11 —R 13  each represents no substitution, mono-, di-, or tri- substitution, and wherein the substituents are the same or different, and each is selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, heteroalkyl, and substituted aryl.  
 
     
     
         52 . The compound of  claim 51 , wherein R 11 , R 12 , and R 13  are each phenyl.  
     
     
         53 . The compound of  claim 51 , wherein the aromatic hydrocarbon material has the structure: