Deep homo (highest occupied molecular orbital) emitter device structures

Abstract

Embodiments of the disclosed subject matter provide an organic light emitting diode (OLED) having an anode, a cathode, an emissive layer disposed between the anode and the cathode, and a hole blocking layer disposed between the emissive and the cathode. The emissive layer may include a phosphorescent dopant, where the phosphorescent dopant has an emission in 0.5% doped PMMA (Poly(methyl methacrylate)) thin film with a peak maximum wavelength that is greater than or equal to 600 nm at room temperature. The energy of a highest occupied molecular orbital (HOMO) of the phosphorescent dopant may be lower than or equal to −5.1 eV, and the energy of the HOMO of the hole blocking layer is at least 0.1 eV lower than the energy of the HOMO of the phosphorescent dopant.

We claim: 
     
         1 . An organic light emitting diode (OLED) comprising:
 an anode;   a cathode;   an emissive layer disposed between the anode and the cathode; and   a hole blocking layer disposed between the emissive and the cathode,   wherein the emissive layer comprises a phosphorescent dopant,   wherein the phosphorescent dopant has an emission with a peak maximum wavelength greater than or equal to 600 nm in 0.5% doped PMMA (Poly(methyl methacrylate)) thin film at room temperature,   wherein the energy of a highest occupied molecular orbital (HOMO) of the phosphorescent dopant is lower than or equal to −5.1 eV, and   wherein the energy of the HOMO of the hole blocking layer is at least 0.2 eV lower than the energy of the HOMO of the phosphorescent dopant.   
     
     
         2 . The OLED of  claim 1 , wherein the peak maximum wavelength of the phosphorescent dopant is greater than or equal to 610 nm, greater than or equal to 620 nm, greater than or equal to 630 nm, greater than or equal to 650 nm, or greater than or equal to 700 nm. 
     
     
         3 . The OLED of  claim 1 , wherein the energy of the HOMO of the phosphorescent dopant is lower than or equal to −5.2 eV, lower than or equal to −5.3 eV, or lower than or equal to −5.4 eV. 
     
     
         4 . The OLED of  claim 1 , wherein the energy of the HOMO of the hole blocking layer is at least 0.3 eV lower than the energy of the HOMO of the phosphorescent dopant, or at least 0.4 eV lower than the energy of the HOMO of the phosphorescent dopant. 
     
     
         5 . The OLED of  claim 1 , wherein the hole blocking layer comprises at least one compound selected from the group consisting of: 
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  each independently represents mono to the maximum allowable substitutions, or no substitution, 
         wherein each R 1  and R 2  is independently a hydrogen or a substituent selected from the group consisting of: deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, 
         wherein Y is selected from the group consisting of: O, S, Se, NAr 4 , CAr 4 Ar 5 , SiAr 4 Ar 5 , Fluorene (C—Ar 1 Ar 2 ), and Silicon (Si—Ar 1 Ar 2 ), and wherein Ar 1  and Ar 2  are the same or different aryl groups, 
         wherein each Ar 1 —Ar 5  is independently selected from the group consisting of: aryl, heteroaryl, and a combination thereof, and 
         wherein L is a direct bond or a linker comprising at least one aromatic ring. 
       
     
     
         6 . The OLED of  claim 5 , wherein each R 1  and R 2  is independently a hydrogen or a substituent selected from the group consisting of: aryl, heteroaryl, and combinations thereof. 
     
     
         7 . The OLED of  claim 5 , wherein Y is selected from the group consisting of O, S, and NAr 4 . 
     
     
         8 . The OLED of  claim 5 , wherein the hole blocking layer comprises only one compound selected from the group consisting of Formula Ia, Formula Ib, Formula Ic, and Formula Id. 
     
     
         9 . The OLED of  claim 5 , wherein the hole blocking layer comprises at least one compound selected from the group consisting of: 
       
         
           
           
               
               
           
         
       
     
     
         10 . The OLED of  claim 1 , wherein the phosphorescent dopant is a metal coordination complex having a metal-carbon bond. 
     
     
         11 . The OLED of  claim 10 , wherein the metal is Ir or Pt. 
     
     
         12 . The OLED of  claim 10 , wherein the metal coordination complex comprises a ligand comprising a chemical moiety selected from the group consisting of: pyridazine, pyrimidine, pyrazine, and triazine. 
     
     
         13 . The OLED of  claim 10 , wherein the metal coordination complex has the formula of M(L 1 ) x (L 2 ) y (L 3 ) z ,
 wherein L 1 , L 2 , and L 3  can be the same or different,   wherein x is 1, 2, or 3,   wherein y is 0, 1, or 2,   wherein z is 0, 1, or 2,   wherein x+y+z is the oxidation state of the metal M,   wherein L 1 , L 2 , and L 3  are each independently selected from the group consisting of:   
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein L 2  and L 3  can also be 
       
       
         
           
           
               
               
           
         
         wherein each Y 1  to Y 1′  are independently selected from the group consisting of carbon and nitrogen, 
         wherein Y′ is selected from the group consisting of B R e , N R e , P R e , O, S, Se, C═O, S═O, SO 2 , CR e R f , SiR e R f , and GeR e R f ; 
         wherein R e  and R f  are optionally fused or joined to form a ring, 
         wherein each R a , R b , R e , and R d  may independently represent from mono substitution to the maximum possible number of substitution, or no substitution, 
         wherein each R a , R b , R e , R d , R e  and R f  is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and 
         wherein any two adjacent substituents of R a , R b , R c , and R d  are optionally fused or joined to form a ring or form a multidentate ligand. 
       
     
     
         14 . The OLED of  claim 13 , wherein L 1 , L 2 , and L 3  are each independently selected from the group consisting of: 
       
         
           
           
               
               
           
         
       
       and wherein L 2  and L 3  can also be 
       
         
           
           
               
               
           
         
       
     
     
         15 . The OLED of  claim 13 , wherein the metal coordination complex has a formula selected from the group consisting of: Ir(L A ) 3 , Ir(L A )(L B ) 2 , Ir(L A ) 2 (L B ), Ir(L A ) 2 (L C ), and Ir(L A )(L B )(L C ); wherein L A , L B , and L C  are different from each other; or a formula of Pt(L A )(L B ),
 wherein L A , and L B  can be same or different, and   wherein L A , and L B  are optionally connected to form a tetradentate ligand.   
     
     
         16 . The OLED of  claim 13 , wherein the metal coordination complex has a formula of Ir(L A ) 2 (L C ),
 wherein L A  is selected from the group consisting of:   
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
       wherein L C  is 
       
         
           
           
               
               
           
         
       
       and
 wherein each R A  and R B  may independently represent from mono substitution to the maximum possible number of substitution, or no substitution, 
 wherein each R A  and R B  is independently selected from the group consisting of: hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and 
 wherein any two adjacent substituents of R A  and R B  are optionally fused or joined to form a ring or form a multidentate ligand. 
 
     
     
         17 . The OLED of  claim 14 , wherein the hole blocking layer comprises at least one compound selected from the group consisting of: 
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  each independently represent mono to the maximum allowable substitution, or no substitution, 
         wherein each R 1  and R 2  is independently a hydrogen or a substituent selected from the group consisting of: deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, 
         wherein Y is selected from the group consisting of: O, S, Se, NAr 4 , CAr 4 Ar 5 , SiAr 4 Ar 5 , Fluorene (C—Ar 1 Ar 2 ), and Silicon (Si—Ar 1 Ar 2 ), and wherein Ar 1  and Ar 2  are the same or different aryl groups, 
         wherein each Ar 1 —Ar 5  is independently selected from the group consisting of: aryl, heteroaryl, and a combination thereof, and 
         wherein L is a direct bond or a linker comprising at least one aromatic ring. 
       
     
     
         18 . The OLED of  claim 14 , wherein the hole blocking layer comprises at least one compound selected from the group consisting of 
       
         
           
           
               
               
           
         
       
     
     
         19 . The OLED of  claim 1 , wherein the OLED further comprises an electron blocking layer, and the electron blocking layer comprises a compound of Formula II: 
       
         
           
           
               
               
           
         
         wherein R 3 , R 4 , and R 5  each independently represent mono to the maximum allowable substitution, or no substitution, 
         wherein each R 3 , R 4 , and R 5  is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and 
         wherein each Ar 5  and Ar 6  is independently selected from the group consisting of aryl, heteroaryl, and combination thereof. 
       
     
     
         20 . A consumer product comprising an organic light emitting diode (OLED) comprising:
 an anode;   a cathode;   an emissive layer disposed between the anode and the cathode; and   a hole blocking layer disposed between the emissive and the cathode,   wherein the emissive layer comprises a phosphorescent dopant,   wherein the phosphorescent dopant has an emission with a peak maximum wavelength greater than or equal to 600 nm at room temperature,   wherein the energy of a highest occupied molecular orbital (HOMO) of the phosphorescent dopant is lower than or equal to −5.1 eV, and   wherein the energy of the HOMO of the hole blocking layer is at least 0.2 eV lower than the energy of the HOMO of the phosphorescent dopant.