Organic electroluminescent materials and devices

1. A compound having a heteroleptic Ir coordination complex structure;

wherein the compound is capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature;

wherein the compound has a first ligand coordinated to a metal;

wherein a free-state of the first ligand has a first triplet energy T1 of E L at 77K;

wherein the compound has a first triplet energy T1 of E L at 77K;

wherein the difference in energy between E and E L is ΔE;

wherein ΔE is ≤250 meV; and

wherein the compound has a triplet emission spectrum with a full width at half maximum (FWHM) value of no more than 45 nm at 22° C.

2. The compound of claim 1 , wherein ΔE is ≤200 meV.

3. The compound of claim 1 , wherein the compound has a metal-carbon bond.

4. The compound of claim 1 , wherein the compound comprises a first benzene ring coordinated to the Ir; and wherein the first benzene ring is fused with a second aromatic ring.

5. The compound of claim 4 , wherein the compound comprises a first benzene ring coordinated to the Ir; and wherein the first benzene ring is fused with a second aromatic ring, wherein the second aromatic ring is fused with a third aromatic ring.

6. The compound of claim 4 , wherein the second aromatic ring is a five-membered ring.

7. The compound of claim 1 , wherein the compound comprises a pyridine ring coordinated to the Ir.

8. The compound of claim 1 , wherein the compound has a formula of Ir(L A ) x (L B ) y (L C ) z wherein L A , L B and L C are each a bidentate ligand; and wherein x is 1 or 2; y is 0, 1, or 2; z is 0, 1, or 2; and x+y+z is 3.

9. The compound of claim 8 , wherein L A is selected from the group consisting of the following Ligand List:

wherein each of L B and L C is independently selected from the group consisting of

and the Ligand List;

wherein each X 1 to X 13 are independently selected from the group consisting of carbon and nitrogen;

wherein X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO 2 , CR′R″, SiR′R″, and GeR′R″;

wherein R′ and R″ are optionally fused or joined to form a ring;

wherein each R a , R b , R c , and R d may represent from mono substitution to the maximum possible number of substitution, or no substitution;

wherein R′, R″, R a , R b , R c , and R d are each independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, 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.

10. The compound of claim 9 , wherein at least one pair of substituents R a , R b , R c , and R d within the same ring are joined and fused into a ring.

11. The compound of claim 9 , wherein x is 1 or 2, y is 1 or 2, L A has a structure of

and L B has a structure of

12. The compound of claim 8 , wherein x is 1 or 2, y is 1 or 2, and L A has the formula:

and

wherein L B is different from L A , and has a formula selected from the group consisting of:

13. The compound of claim 8 , wherein the compound has a formula selected from the group consisting of 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 ); and wherein L A , L B , and L C are different from each other.

14. A formulation comprising a compound according to claim 1 .

15. An organic light emitting device (OLED) comprising:

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, comprising a compound having a heteroleptic Ir coordination complex structure;

wherein the compound is capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature;

wherein the compound has a first ligand coordinated to a metal;

wherein a free-state of the first ligand has a first triplet energy T1 of E L at 77K;

wherein the compound has a first triplet energy T1 of E L at 77K;

wherein the difference in energy between E and E L is ΔE;

wherein ΔE is ≤250 meV; and

wherein the compound has a triplet emission spectrum with a full width at half maximum (FWHM) value of no more than 45 nm at 22° C.

16. The OLED of claim 15 , wherein the organic layer is an emissive layer and the compound is an emissive dopant or a non-emissive dopant.

17. The OLED of claim 15 , wherein the organic layer further comprises a host, wherein host comprises at least one chemical group selected from the group consisting of triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

18. The OLED of claim 17 , wherein the host is selected from the group consisting of:

and combinations thereof.

19. A consumer product comprising an organic light-emitting device (OLED) comprising:

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, comprising a compound having a heteroleptic Ir coordination complex structure;

wherein the compound is capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature;

wherein the compound has a first ligand coordinated to a metal;

wherein a free-state of the first ligand has a first triplet energy T1 of E L at 77K;

wherein the compound has a first triplet energy T1 of E at 77K;

wherein the difference in energy between E and E L is ΔE;

wherein ΔE is ≤250 meV; and

wherein the compound has a triplet emission spectrum with a full width at half maximum (FWHM) value of no more than 45 nm at 22° C.

20. The consumer product of claim 19 , wherein the consumer product is selected from the group consisting of a flat panel display, a curved display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a rollable display, a foldable display, a stretchable display, a laser printer, a telephone, a mobile phone, a tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display that is less than 2 inches diagonal, a 3-D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, and a sign.