Organic electroluminescent materials and devices

1. A composition comprising a mixture of a first compound and a second compound,

wherein the first compound is selected from the group consisting of:

wherein X 1 and X 2 are each independently selected from the group consisting of CR 4 R 5 , O, S and Se;

wherein R 1 to R 3 each independently represent mono to the possible maximum number of substitution, or no substitution;

wherein R 1 to R 3 each independently represent mono to the possible maximum number of substitution, or no substitution;

wherein (i) G 2 comprises a moiety selected from the group consisting of dibenzofuran, dibenzothiophene, dibenzoselenophene, fluorene, triphenylene, and combinations thereof, or

(ii) G 2 comprises a moiety selected from the group consisting of phenanthroline, azadibenzofuran, azadibenzothiophene, azadibenzoselenophene, azafluorene, azatriphenylene, and combinations thereof;

wherein R 2 , R 3 , R 4 , and R 5 are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and wherein any two adjacent substituents can optionally join or fuse into a ring;

wherein at least one of option (a) or option (b) is true:

(a) X 1 or X 2 is present and represents Se;

(b)(1)(i) the first compounds has the structure of GH2 or GH3, or (1)(ii) the first compound has a structure of GH1, GH4, or GH5, and two R 2 are not joined to form a ring, and

(2) at least one of R 1 and R 3 is unsubstituted, and

(3) G 2 is selected from the group consisting of dibenzoselenophene, phenanthroline, azadibenzofuran, azadibenzoselenophene, azafluorene, and combinations thereof;

with the proviso that none of R 1 , R 2 , R 3 , R 4 , or R 5 is triphenylene;

wherein the second compound has a formula Ir(L A ) n (L B ) 3-n , and having the structure according to Formula II

wherein each A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 comprise carbon or nitrogen;

wherein ring B is bonded to ring A through a C—C bond;

wherein the iridium is bonded to ring A through a Ir—C bond;

wherein X 3 is selected from a group consisting of O, S and Se;

wherein R 7 to R 11 each independently represent mono to the possible maximum number of substitution, or no substitution;

wherein R 7 to R 11 are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and

wherein any two adjacent substituents can optionally join or fuse into a ring; and

wherein n is an integer from 1 to 3.

2. The composition of claim 1 , wherein G 2 is further substituted.

3. The composition of claim 1 , wherein the first compound is selected from the group consisting of:

4. The composition of claim 1 , wherein the second compound has the formula:

5. The composition of claim 1 , wherein X 3 is O.

6. The composition of claim 1 , wherein L A is selected from the group consisting of:

7. The composition of claim 1 , wherein the second compound is selected from the group consisting of:

8. The composition comprising a mixture of a first compound and a second compound, wherein the first compound and the second compound are selected in pairs from the group consisting of (Compound HA26, Compound D151), (Compound HA30, Compound D87), (Compound HA33, Compound D13), (Compound HA34, Compound D85), (Compound HA52, Compound D85), and (Compound HA68, Compound D151),

wherein the first compounds are defined as

and

wherein the second compounds are defined as follows:

9. The composition of claim 1 , wherein the first compound has an evaporation temperature T1 of 150 to 350° C.;

wherein the second compound has an evaporation temperature T2 of 150 to 350° C.;

wherein absolute value of T1-T2 is less than 20° C.;

wherein the first compound has a concentration C1 in said mixture and a concentration C2 in a film formed by evaporating the mixture in a vacuum deposition tool at a constant pressure between 1×10 −6 Torr to 1×10 −9 Torr, at a 2Å/sec deposition rate on a surface position at a predefined distance away from the mixture being evaporated; and

wherein absolute value of (C1-C2)/C1 is less than 5%.

10. The composition of claim 1 , wherein the first compound has a vapor pressure of P1 at T1 at 1 atm, the second compound has a vapor pressure of P2 at T2 at 1 atm; and

wherein the ratio of P1/P2 is within the range of 0.90 to 1.10.

11. The composition of claim 1 , wherein first compound has a first mass loss rate and the second compound has a second mass loss rate, wherein the ratio between the first mass loss rate and the second mass loss rate is within the range of 0.90 to 1.10.

12. A method for fabricating an organic light emitting device, the method comprising:

placing a premixed VTE evaporation source in an evaporation crucible;

providing a substrate having a first electrode disposed thereon;

depositing a first organic layer over the first electrode by evaporating the premixed VTE evaporation source from the evaporation crucible, wherein the premixed VTE evaporation source is a mixture of a first compound and a second compound in a vacuum deposition tool at a constant pressure between 1×10 −6 Torr to 1×10 −9 Torr, at a 2Å/sec deposition rate on a surface position at a predefined distance away from the mixture being evaporated; and

depositing a second electrode over the first organic layer;

wherein the first compound is selected from the group consisting of:

wherein X 1 and X 2 are each independently selected from the group consisting of CR 4 R 5 , O, S and Se;

wherein R 1 to R 3 each independently represent mono to the possible maximum number of substitution, or no substitution;

wherein R 1 to R 3 each independently represent mono to the possible maximum number of substitution, or no substitution;

wherein (i) G 2 comprises a moiety selected from the group consisting of dibenzofuran, dibenzothiophene, dibenzoselenophene, fluorene, triphenylene, and combinations thereof, or

(ii) G 2 comprises a moiety selected from the group consisting of phenanthroline, azadibenzofuran, azadibenzothiophene, azadibenzoselenophene, azafluorene, azatriphenylene, and combinations thereof;

wherein R 1 , R 2 , R 3 , R 4 , and R 5 are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and wherein any two adjacent substituents can optionally join or fuse into a ring;

wherein at least one of option (a) or option (b) is true:

(a) X 1 or X 2 is present and represents Se;

(b)(1)(i) the first compounds has the structure of GH2 or GH3, or (1)(ii) the first compound has a structure of GH1, GH4, or GH5, and two le are not joined to form a ring, and

(2) at least one of R 1 and R 3 is unsubstituted, and

(3) G 2 is selected from the group consisting of dibenzoselenophene, phenanthroline, azadibenzofuran, azadibenzoselenophene, azafluorene, and combinations thereof;

with the proviso that none of R 1 , R 2 , R 3 , R 4 , or R 5 is triphenylene;

wherein the second compound has a formula Ir(L A ) n (L B ) 3-n , and having the structure according to Formula II

wherein each A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 comprise carbon or nitrogen;

wherein ring B is bonded to ring A through a C—C bond;

wherein the iridium is bonded to ring A through a Ir—C bond;

whererin X 3 is selected from a group consisting of O, S and Se;

wherein R 7 to R 11 each independently represent mono to the possible maximum number of substitution, or no substitution;

wherein R 7 to R 11 are each independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and

wherein any two adjacent substituents can optionally join or fuse into a ring; and

wherein n is an integer from 1 to 3.

13. A composition comprising a first compound and a second compound selected in pairs from the group consisting of

14. The composition of claim 3 , wherein the second compound is selected from the group consisting of:

15. The composition of claim 1 , wherein (a) X 1 or X 2 is present and represents Se.

16. The composition of claim 1 , wherein (b)(1)(i) the first compounds has the structure of GH2 or GH3, and

(2) at least one of R 1 and R 3 is unsubstituted, and

(3)(i) G 2 is selected from the group consisting of dibenzoselenophene, phenanthroline, azadibenzofuran, azadibenzoselenophene, azafluorene, and combinations thereof.

17. The composition of claim 1 , wherein (1)(ii) the first compound has a structure of GH1, GH4, or GH5, and two le are not joined to form a ring, and

(2) at least one of le and R 3 is unsubstituted, and

(3)(i) G 2 is selected from the group consisting of dibenzoselenophene, phenanthroline, azadibenzofuran, azadibenzoselenophene, azafluorene, and combinations thereof.