Triaryl amine thick layer doped with metal amides for use as HIL for an organic light-emitting diode (OLED)

Abstract

The present invention relates to a hole injection layer for an OLED comprising a triarylamine compound doped with a charge neutral metal amide compound, characterized in that the hole injection layer has a thickness of at least about ≥20 nm to about ≤1000 nm and the charge neutral metal amide compound has the Formula Ia. ##STR00001##

Claims

1. An OLED, comprising: an anode, a hole injection laver, a hole transport layer, and an emission layer, wherein the hole injection layer is in direct contact with the anode and comprises triarylamine compound (VIIa) doped with a charge neutral metal amide compound (Ia), characterized in that the hole injection layer has a thickness of at least about ≥20 nm to about ≤1000 nm and the charge neutral metal amide compound has the Formula Ia: ##STR00228## wherein: G=halide, O, alkoxylate or amine of Formula IIa to IIe: ##STR00229## R.sup.1 to R.sup.5 are independently selected from the group comprising H, C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, unsubstituted or C.sub.1 to C.sub.12 substituted C.sub.6 to C.sub.20 aryl, unsubstituted or C.sub.1 to C.sub.12 substituted heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; or at least one R.sup.1 and R.sup.4 and/or R.sup.2 and R.sup.3 and/or R.sup.1 and R.sup.5 are bridged and form a 5 to 20 member ring; m=0, 1, 2, 3 or 4; M=a metal selected from the group comprising alkali metal, alkaline earth metal, Al, Ga, In, transition metal or rare earth metal; wherein the bond between N and the metal M is a covalent bond or N forms a non-covalent interaction to the metal M; L=charge neutral ligand which coordinates to the metal M, selected from the group comprising H.sub.2O, C.sub.2 to C.sub.40 mono- or multi-dentate ethers and C.sub.2 to C.sub.40 thioethers, C.sub.2 to C.sub.40 amines, C.sub.2 to C.sub.40 phosphine, C.sub.2 to C.sub.20 alkyl nitrile or C.sub.2 to C.sub.40 aryl nitrile, or a compound according to Formula (III); ##STR00230## wherein R.sup.6 and R.sup.7 are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, C.sub.6 to C.sub.20 aryl, heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms, or at least one R.sup.6 and R.sup.7 are bridged and form a 5 to 20 member ring, or the two R.sup.6 and/or the two R.sup.7 are bridged and form a 5 to 40 member ring or form a 5 to 40 member ring comprising an unsubstituted or C.sub.1 to C.sub.12 substituted phenanthroline; p=0, 1, 2 or 3; A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are independently selected from CO, SO.sub.2 or POR.sup.8; R.sup.8=electron withdrawing group selected from the group comprising halide, nitrile, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, or halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; n=1, 2, 3, 4 or 5; B.sup.1, B.sup.2, B.sup.3 and B.sup.4 are same or independently selected from substituted or unsubstituted C.sub.1 to C.sub.20 alkyl, substituted or unsubstituted C.sub.1 to C.sub.20 heteroalkyl, substituted or unsubstituted C.sub.6 to C.sub.20 aryl, substituted or unsubstituted C.sub.5 to C.sub.20 heteroaryl, or B.sup.1 and B.sup.2 are bridged; wherein B.sup.1 and B.sup.2 are bridged, then: M, N, A.sup.1, B.sup.1, B.sup.2, A.sup.2 and N form a 7 to 10 member ring according to Formula Ib; ##STR00231##  or N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a 5 to 10 member ring according to Formula Ic, ##STR00232##  or N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a first 5 to 10 member ring and B.sup.1 and B.sup.2 form a second 5 to 20 member ring according to Formula Id: ##STR00233##

2. The OLED according to claim 1, wherein the triarylamine compound has the Formula VIIa: ##STR00234## wherein: Ar.sup.1 and Ar.sup.2=independently selected from substituted or unsubstituted C.sub.6 to C.sub.20 arylene; Ar.sup.3 and Ar.sup.4=independently selected from substituted or unsubstituted C.sub.6 to C.sub.20 aryl; Ar.sup.5 and Ar.sup.6=independently selected from substituted or unsubstituted C.sub.6 to C.sub.20 aryl or C.sub.5 to C.sub.40 heteroaryl; R.sup.9=a single chemical bond, a unsubstituted or substituted C.sub.1 to C.sub.6 alkyl and unsubstituted or substituted C.sub.1 to C.sub.5 heteroalkyl; q=0, 1 or 2; r=0 or 1; wherein the substituents for Ar.sup.1 to Ar.sup.6 are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, or halide; and the substitutents for R.sup.9 are independently selected from C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.5 heteroalkyl, C.sub.6 to C.sub.20 aryl and C.sub.5 to C.sub.20 heteroaryl; wherein the charge neutral metal amide compound has the Formula Ia, Ib, Ic or Id.

3. The OLED according to claim 1, wherein: one triarylamine compound is present in the hole injection layer; or one charge neutral metal amide compound is present in the hole injection layer; or one triarylamine compound and one charge neutral metal amide compound are present in the hole injection layer.

4. The OLED according to claim 1, wherein the charge neutral metal amide compound has the Formula Ia, ##STR00235## wherein: A.sup.1 and A.sup.2 are same or independently selected from CO, POR.sup.8 and SO.sub.2, or A.sup.1 and A.sup.2 are independently selected from CO, POR.sup.8, SO.sub.2, and N, A.sup.1, B.sup.1, A.sup.2 and B.sup.2 form a 5 to 10 member ring.

5. The OLED according to claim 1, wherein for: p=0, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IIa: ##STR00236##  or p=1, 2 or 3, and n=1, 2, 3 or 4 and m=0, the charge neutral metal amide compound has the Formula IIb: ##STR00237##  or p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula IIc: ##STR00238##  or p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a first 5 to 10 member ring and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IId: ##STR00239##  or p=1, 2 or 3, n=1, m=1, 2, 3 or 4, and M, N, A.sup.1, B.sup.1, B.sup.2, A.sup.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula IIe: ##STR00240## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula IIf: ##STR00241## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IIg: ##STR00242## p=1, 2 or 3, n=1, m=0 and M, N, A.sup.1, B.sup.1, B.sup.2, A.sup.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula ##STR00243##

6. The OLED according to claim 1, wherein for A.sup.1 and A.sup.2 are SO.sub.2: p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IIIa: ##STR00244## p=0, n=1, 2, 3 or 4, m=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IIIb: ##STR00245## p=1, 2 or 3, n=1, 2, 3 or 4, m=0, the charge neutral metal amide compound has the Formula IIIc: ##STR00246## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula IIId: ##STR00247## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IIIe: ##STR00248## p=1, 2 or 3, n=1, m=1, 2, 3 or 4 and M, N, SO.sub.2, B.sup.1, B.sup.2, SO.sub.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula IIIf: ##STR00249## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula IIIg: ##STR00250## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IIIh: ##STR00251## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and M, N, SO.sub.2, B.sup.1, B.sup.2, SO.sub.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula IIIi: ##STR00252## wherein for A.sup.1 and A.sup.2 are POR.sup.8: p=1, 2 or 3, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IVa: ##STR00253## p=0, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IVb: ##STR00254## p=1, 2 or 3, m=0 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IVc: ##STR00255## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, POR.sup.8, B.sup.1, B.sup.2 and POR.sup.8 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula (IVd): ##STR00256## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, POR.sup.8, B.sup.1, B.sup.2 and POR.sup.8 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula (IVe): ##STR00257## wherein for A.sup.1 and A.sup.2 are CO: p=1, 2 or 3, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula Va: ##STR00258## p=0, n=1, 2, 3 or 4, m=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula Vb: ##STR00259## p=1, 2 or 3, n=1, 2, 3 or 4, m=0, the charge neutral metal amide compound has the Formula Vc: ##STR00260## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, CO, B.sup.1, B.sup.2 and CO form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula Vd: ##STR00261## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, CO, B.sup.1, B.sup.2 and CO form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula Ve: ##STR00262## p=1, 2 or 3, n=1, m=1, 2, 3 or 4 and M, N, CO, B.sup.1, B.sup.2, CO and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula Vf: ##STR00263## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, CO, B.sup.1, B.sup.2 and CO form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula (Vg): ##STR00264## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, CO, B.sup.1, B.sup.2 and CO form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula Vh: ##STR00265## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and M, N, CO, B.sup.1, B.sup.2, CO and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula (Vi): ##STR00266##  or wherein for A.sup.1 is SO.sub.2 and A.sup.2 is POR.sup.8: p=1, 2 or 3, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula VIa: ##STR00267##

7. The OLED according to claim 1, wherein B.sup.1, B.sup.2, B.sup.3 and B.sup.4 are independently selected from a substituted C.sub.1 to C.sub.20 alkyl, substituted C.sub.1 to C.sub.20 heteroalkyl, substituted C.sub.6 to C.sub.20 aryl, or substituted C.sub.5 to C.sub.20 heteroaryl; wherein the substituent is an electron withdrawing group selected from the group comprising a halide, nitrile, perhalogenated C.sub.1 to C.sub.20 alkyl, perhalogenated C.sub.6 to C.sub.20 aryl, perhalogenated heteroaryl with 6 to 20 ring-forming atoms.

8. The OLED according to claim 1, wherein m=0, 1 or 2.

9. The OLED according to claim 1, wherein M is selected from Li(I), Na(I), K(I), Cs(I), Mg(II), Ca(II), Sr(II), Ba(II), Sc(III), Y(III), Ti(IV), V(III-V), Cr(III-VI), Mn(II), Mn(III), Fe(II), Fe(III), Co(II), Co(III), Ni(II), Cu(I), Cu(II), Zn(II), Ag(I), Au(I), Au(III), Al(III), Ga(III), In(III), Sn(II), Sn(IV), or Pb(II).

10. The OLED according to claim 1, wherein the charge neutral metal amide compound has the Formula Ib: ##STR00268## wherein A.sup.3 and A.sup.4 are same or independently selected from CO, POR.sup.8 or SO.sub.2; B.sup.3 and B.sup.4 are independently selected from substituted or unsubstituted C.sub.1 to C.sub.20 alkyl, substituted or unsubstituted C.sub.1 to C.sub.20 heteroalkyl, substituted or unsubstituted C.sub.6 to C.sub.20 aryl, substituted or unsubstituted C.sub.6 to C.sub.20 heteroaryl; and M, N, A.sup.1, B.sup.1, A.sup.2 and B.sup.2 form a 7 to 10 member ring.

11. The OLED according to claim 1, wherein N, A.sup.1, B.sup.1, A.sup.2 and B.sup.2 form a first 5 to 10 member ring and B.sup.1 and B.sup.2 according to Formula Id: ##STR00269## are bridged to form a second ring of a substituted or unsubstituted C.sub.6 to C.sub.20 aryl, or of a substituted or unsubstituted C.sub.6 to C.sub.20 heteroaryl ring.

12. The OLED according to claim 1, wherein the charge neutral metal amide compound is selected from at least one of the fluorinated compounds according to Formula C1 to C25: wherein Formula C1 to C16, wherein p=0, m=0, n=1, 2, 3 or 4 and A.sup.1 and A.sup.2 are SO.sub.2: ##STR00270## ##STR00271## ##STR00272## Formula C17 to C23, wherein n=1, 2, 3 or 4, A.sup.1 and A.sup.2 are CO: ##STR00273## Formula C24 to C25, wherein n=1, 2, 3 or 4, A.sup.1 and A.sup.2 are POR.sup.8: ##STR00274##

13. The OLED according to claim 1, wherein the charge neutral metal amide compound is selected from at least one fluorinated compound according to Formula D1 to D24: wherein p=0, m=0, n=1, 2, 3 or 4 and A.sup.1 and A.sup.2 are SO.sub.2: ##STR00275## ##STR00276## ##STR00277## ##STR00278##

14. The OLED according to claim 1, wherein the charge neutral metal amide compound is selected from at least one fluorinated compound according to Formula F1 to F23: wherein the charge neutral ligand L coordinates to the metal M: ##STR00279## ##STR00280## ##STR00281## wherein R.sup.6 and R.sup.7 are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, C.sub.6 to C.sub.20 aryl, heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms, or at least one R.sup.6 and R.sup.7 are bridged and form a 5 to 20 member ring, or the two R.sup.6 and/or the two R.sup.7 are bridged and form a 5 to 40 member ring or form a 5 to 40 member ring comprising an unsubstituted or C.sub.1 to C.sub.12 substituted phenanthroline.

15. The OLED according to claim 1, wherein the charge neutral metal amide compound is selected from at least one fluorinated compound according to Formula F24 to F45: wherein a halide, O, alkoxylate or amine bonds to the metal M: ##STR00282## ##STR00283## ##STR00284## ##STR00285## wherein R.sup.1 to R.sup.5 are independently selected from the group comprising H, C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, unsubstituted or C.sub.1 to C.sub.12 substituted C.sub.6 to C.sub.20 aryl, unsubstituted or C.sub.1 to C.sub.12 substituted heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; or at least one R.sup.1 and R.sup.4 and/or R.sup.2 and R.sup.3 and/or R.sup.1 and R.sup.5 are bridged and form a 5 to 20 member cyclic ring.

16. The OLED according to claim 1, wherein for the triarylamine compound having the Formula VIIa: Ar.sup.1 and Ar.sup.2 are independently selected from phenylene, biphenylene, naphthylene, anthranylene, carbazolylene and fluorenylene; Ar.sup.3 to Ar.sup.6 are independently selected from phenyl, biphenyl, terphenyl, quartphenyl, fluorenyl, napthyl, anthranyl, phenanthryl, thiophenyl, fluorenyl, 9-carbazolyl.

17. The OLED according to claim 1, wherein the triarylamine compound has the Formula VIIb to VIIk: ##STR00286## ##STR00287##

18. The OLED according to claim 1, wherein the hole injection layer is in direct contact with the anode and the emission layer is in direct contact with the hole injection layer.

19. The OLED according to claim 1, comprising: a hole transport layer arranged between the hole injection layer and the emission layer, wherein the hole injection layer is in direct contact with the anode and the hole transport layer is in direct contact with the hole injection layer; and wherein the composition of the hole injection layer is different to the composition of the hole transport layer.

20. A hole injection layer for an OLED, the hole injection layer comprising a triarylamine compound (VIIa) doped with a charge neutral metal amide compound (Ia), characterized in that the hole injection layer has a thickness of at least about ≥20 nm to about ≤1000 nm and the charge neutral metal amide compound has the Formula Ia: ##STR00288## wherein: G=halide, O, alkoxylate or amine of Formula IIa to IIe: ##STR00289## R.sup.1 to R.sup.5 are independently selected from the group comprising H, C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, unsubstituted or C.sub.1 to C.sub.12 substituted C.sub.6 to C.sub.20 aryl, unsubstituted or C.sub.1 to C.sub.12 substituted heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; or at least one R.sup.1 and R.sup.4 and/or R.sup.2 and R.sup.3 and/or R.sup.1 and R.sup.5 are bridged and form a 5 to 20 member ring; m=0, 1, 2, 3 or 4; M=a metal selected from the group comprising alkali metal, alkaline earth metal, Al, Ga, In, transition metal or rare earth metal; wherein the bond between N and the metal M is a covalent bond or N forms a non-covalent interaction to the metal M; L=charge neutral ligand which coordinates to the metal M, selected from the group comprising H.sub.2O, C.sub.2 to C.sub.40 mono- or multi-dentate ethers and C.sub.2 to C.sub.40 thioethers, C.sub.2 to C.sub.40 amines, C.sub.2 to C.sub.40 phosphine, C.sub.2 to C.sub.20 alkyl nitrile or C.sub.2 to C.sub.40 aryl nitrile, or a compound according to Formula (III); ##STR00290## wherein R.sup.6 and R.sup.7 are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, C.sub.6 to C.sub.20 aryl, heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms, or at least one R.sup.6 and R.sup.7 are bridged and form a 5 to 20 member ring, or the two R.sup.6 and/or the two R.sup.7 are bridged and form a 5 to 40 member ring or form a 5 to 40 member ring comprising an unsubstituted or C.sub.1 to C.sub.12 substituted phenanthroline; p=0, 1, 2 or 3; A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are independently selected from CO, SO.sub.2 or POR.sup.8; R.sup.8=electron withdrawing group selected from the group comprising halide, nitrile, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, or halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; n=1, 2, 3, 4 or 5; B.sup.1, B.sup.2, B.sup.3 and B.sup.4 are same or independently selected from substituted or unsubstituted C.sub.1 to C.sub.20 alkyl, substituted or unsubstituted C.sub.1 to C.sub.20 heteroalkyl, substituted or unsubstituted C.sub.6 to C.sub.20 aryl, substituted or unsubstituted C.sub.5 to C.sub.20 heteroaryl, or B.sup.1 and B.sup.2 are bridged; wherein B.sup.1 and B.sup.2 are bridged, then: M, N, A.sup.1, B.sup.1, B.sup.2, A.sup.2 and N form a 7 to 10 member ring according to Formula Ib; ##STR00291##  or N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a 5 to 10 member ring according to Formula Ic, ##STR00292##  or N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a first 5 to 10 member ring and B.sup.1 and B.sup.2 form a second 5 to 20 member ring according to Formula Id: ##STR00293## wherein for: p=0, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IIa: ##STR00294##  or p=1, 2 or 3, and n=1, 2, 3 or 4 and m=0, the charge neutral metal amide compound has the Formula IIb: ##STR00295##  or p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula IIc: ##STR00296##  or p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a first 5 to 10 member ring and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IId: ##STR00297##  or p=1, 2 or 3, n=1, m=1, 2, 3 or 4, and M, N, A.sup.1, B.sup.1, B.sup.2, A.sup.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula IIe: ##STR00298## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula IIf: ##STR00299## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IIg: ##STR00300## p=1, 2 or 3, n=1, m=0 and M, N, A.sup.1, B.sup.1, B.sup.2, A.sup.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula IIh: ##STR00301##

21. A hole injection layer for an OLED, the hole injection layer comprising a triarylamine compound (VIIa) doped with a charge neutral metal amide compound (Ia), characterized in that the hole injection layer has a thickness of at least about ≥20 nm to about ≤1000 nm and the charge neutral metal amide compound has the Formula Ia: ##STR00302## wherein: G=halide, O, alkoxylate or amine of Formula IIa to IIe: ##STR00303## R.sup.1 to R.sup.5 are independently selected from the group comprising H, C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, unsubstituted or C.sub.1 to C.sub.12 substituted C.sub.6 to C.sub.20 aryl, unsubstituted or C.sub.1 to C.sub.12 substituted heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; or at least one R.sup.1 and R.sup.4 and/or R.sup.2 and R.sup.3 and/or R.sup.1 and R.sup.5 are bridged and form a 5 to 20 member ring; m=0, 1, 2, 3 or 4; M=a metal selected from the group comprising alkali metal, alkaline earth metal, Al, Ga, In, transition metal or rare earth metal; wherein the bond between N and the metal M is a covalent bond or N forms a non-covalent interaction to the metal M; L=charge neutral ligand which coordinates to the metal M, selected from the group comprising H.sub.2O, C.sub.2 to C.sub.40 mono- or multi-dentate ethers and C.sub.2 to C.sub.40 thioethers, C.sub.2 to C.sub.40 amines, C.sub.2 to C.sub.40 phosphine, C.sub.2 to C.sub.20 alkyl nitrile or C.sub.2 to C.sub.40 aryl nitrile, or a compound according to Formula (III); ##STR00304## wherein R.sup.6 and R.sup.7 are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 to C.sub.20 heteroalkyl, C.sub.6 to C.sub.20 aryl, heteroaryl with 5 to 20 ring-forming atoms, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.1 to C.sub.20 heteroalkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms, or at least one R.sup.6 and R.sup.7 are bridged and form a 5 to 20 member ring, or the two R.sup.6 and/or the two R.sup.7 are bridged and form a 5 to 40 member ring or form a 5 to 40 member ring comprising an unsubstituted or C.sub.1 to C.sub.12 substituted phenanthroline; p=0, 1, 2 or 3; A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are independently selected from CO, SO.sub.2 or POR.sup.8; R.sup.8=electron withdrawing group selected from the group comprising halide, nitrile, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, or halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; n=1, 2, 3, 4 or 5; B.sup.1, B.sup.2, B.sup.3 and B.sup.4 are same or independently selected from substituted or unsubstituted C.sub.1 to C.sub.20 alkyl, substituted or unsubstituted C.sub.1 to C.sub.20 heteroalkyl, substituted or unsubstituted C.sub.6 to C.sub.20 aryl, substituted or unsubstituted C.sub.5 to C.sub.20 heteroaryl, or B.sup.1 and B.sup.2 are bridged; wherein B.sup.1 and B.sup.2 are bridged, then: M, N, A.sup.1, B.sup.1, B.sup.2, A.sup.2 and N form a 7 to 10 member ring according to Formula Ib; ##STR00305##  or N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a 5 to 10 member ring according to Formula Ic, ##STR00306##  or N, A.sup.1, B.sup.1, B.sup.2 and A.sup.2 form a first 5 to 10 member ring and B.sup.1 and B.sup.2 form a second 5 to 20 member ring according to Formula Id: ##STR00307## wherein for A.sup.1 and A.sup.2 are SO.sub.2: p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IIIa: ##STR00308## p=0, n=1, 2, 3 or 4, m=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IIIb: ##STR00309## p=1, 2 or 3, n=1, 2, 3 or 4, m=0, the charge neutral metal amide compound has the Formula IIIc: ##STR00310## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula TIM: ##STR00311## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IIIe: ##STR00312## p=1, 2 or 3, n=1, m=1, 2, 3 or 4 and M, N, SO.sub.2, B.sup.1, B.sup.2, SO.sub.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula IIIf: ##STR00313## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula IIIg: ##STR00314## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, SO.sub.2, B.sup.1, B.sup.2 and SO.sub.2 form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula IIIh: ##STR00315## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and M, N, SO.sub.2, B.sup.1, B.sup.2, SO.sub.2 and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula IIIi: ##STR00316## wherein for A.sup.1 and A.sup.2 are POR.sup.8: p=1, 2 or 3, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IVa: ##STR00317## p=0, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IVb: ##STR00318## p=1, 2 or 3, m=0 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula IVc: ##STR00319## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, POR.sup.8, B.sup.1, B.sup.2 and POR.sup.8 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula (IVd): ##STR00320## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, POR.sup.8, B.sup.1, B.sup.2 and POR.sup.8 form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula (IVe): ##STR00321## wherein for A.sup.1 and A.sup.2 are CO: p=1, 2 or 3, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula Va: ##STR00322## p=0, n=1, 2, 3 or 4, m=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula Vb: ##STR00323## p=1, 2 or 3, n=1, 2, 3 or 4, m=0, the charge neutral metal amide compound has the Formula Vc: ##STR00324## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, CO, B.sup.1, B.sup.2 and CO form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula Vd: ##STR00325## p=1, 2 or 3, n=1, 2, 3 or 4, m=1, 2, 3 or 4 and N, CO, B.sup.1, B.sup.2 and CO form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 are bridged to form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula Ve: ##STR00326## p=1, 2 or 3, n=1, m=1, 2, 3 or 4 and M, N, CO, B.sup.1, B.sup.2, CO and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula Vf: ##STR00327## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, CO, B.sup.1, B.sup.2 and CO form a 5 to 10 member ring, the charge neutral metal amide compound has the Formula (Vg): ##STR00328## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and N, CO, B.sup.1, B.sup.2 and CO form a first 5 to 10 member ring, and B.sup.1 and B.sup.2 form a second 5 to 20 member ring, the charge neutral metal amide compound has the Formula Vh: ##STR00329## p=1, 2 or 3, n=1, 2, 3 or 4, m=0 and M, N, CO, B.sup.1, B.sup.2, CO and N form a 7 to 10 member ring, the charge neutral metal amide compound has the Formula (Vi): ##STR00330##  or wherein for A.sup.1 is SO.sub.2 and A.sup.2 is POR.sup.8: p=1, 2 or 3, m=1, 2, 3 or 4 and n=1, 2, 3 or 4, the charge neutral metal amide compound has the Formula VIa: ##STR00331##

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings, of which:

(2) FIG. 1 is a schematic sectional view of an organic light-emitting diode (OLED), according to an exemplary embodiment of the present invention;

(3) FIG. 2 is a schematic sectional view of an OLED, according to an exemplary embodiment of the present invention.

(4) FIG. 3 is a schematic sectional view of an OLED, according to an exemplary embodiment of the present invention.

(5) FIG. 4 is an overview of metal amides based on general Formula Ia that can be used according to the invention.

(6) FIG. 5 is an overview of metal amides that can be used according to the invention with specific A.sup.1 and A.sup.2, wherein A.sup.1 and A.sup.2 are SO.sub.2.

(7) FIG. 6 is an overview of metal amides that can be used according to the invention with specific A.sup.1 and A.sup.2, wherein A.sup.1 and A.sup.2 are POR.sup.8.

(8) FIG. 7 is an overview of metal amides that can be used according to the invention with specific A.sup.1 and A.sup.2, wherein A.sup.1 and A.sup.2 are CO.

(9) FIG. 8 is an overview of metal amides that can be used according to the invention with specific A.sup.1 and A.sup.2, wherein A.sup.1 and A.sup.2 are selected different, wherein A.sup.1 is SO.sub.2 and A.sup.2 is POR.sup.8.

DETAILED DESCRIPTION

(10) Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The exemplary embodiments are described below, in order to explain the aspects of the present invention, by referring to the figures.

(11) Herein, when a first element is referred to as being formed or disposed “on” a second element, the first element can be disposed directly on the second element, or one or more other elements may be disposed there between. When a first element is referred to as being formed or disposed “directly on” a second element, no other elements are disposed there between.

(12) FIG. 1 is a schematic sectional view of an organic light-emitting diode (OLED) 100, according to an exemplary embodiment of the present invention. The OLED 100 includes a substrate 110. On the substrate 110 an anode 120 is disposed. On the anode 120 a hole injection layer 130 containing or consisting of a metal amide compound according to the invention is disposed and thereon a hole transport layer 140. Onto the hole transport layer 140 an emission layer 150 and an cathode electrode 190, exactly in this order, are disposed.

(13) FIG. 2 is a schematic sectional view of an organic light-emitting diode (OLED) 100, according to an exemplary embodiment of the present invention. The OLED 100 includes a substrate 110, a first electrode 120, a hole injection layer (HIL) 130, a hole transport layer (HTL) 140, an emission layer (EML) 150, an electron transport layer (ETL) 161. The electron transport layer (ETL) 161 is formed directly on the EML 150. Onto the electron transport layer (ETL) 161 a cathode electrode 190 is disposed.

(14) Instead of a single electron transport layer 161, optional an electron transport layer stack (ETL) can be used.

(15) FIG. 3 is a schematic sectional view of an OLED 100, according to another exemplary embodiment of the present invention. FIG. 3 differs from FIG. 2 in that the OLED 100 of FIG. 3 comprises a hole blocking layer (HBL) 155 and an electron injection layer (EIL) 180.

(16) Referring to FIG. 3 the OLED 100 includes a substrate 110, an anode electrode 120, a hole injection layer (HIL) 130, a hole transport layer (HTL) 140, an emission layer (EML) 150, a hole blocking layer (HBL) 155, an electron transport layer (ETL) 161, an electron injection layer (EIL) 180 and a cathode electrode 190. The layers are disposed exactly in the order as mentioned before.

(17) In the description above the method of manufacture an OLED of the present invention is started with a substrate 110 onto which an anode electrode 120 is formed, on the anode electrode 120, an hole injection layer 130, hole transport layer 140, an emission layer 150, optional a hole blocking layer 155, optional at least one electron transport layer 161, optional at least one electron injection layer 180, and a cathode electrode 190 are formed, exactly in that order or exactly the other way around.

(18) While not shown in FIG. 1, FIG. 2 and FIG. 3, a sealing layer may further be formed on the cathode electrodes 190, in order to seal the OLEDs 100. In addition, various other modifications may be applied thereto.

(19) Hereinafter, one or more exemplary embodiments of the present invention will be described in detail with, reference to the following examples. However, these examples are not intended to limit the purpose and scope of the one or more exemplary embodiments of the present invention.

EXAMPLES

(20) General Procedure

(21) For bottom emission devices, a 15 Ω/cm.sup.2 glass substrate (available from Corning Co.) with 100 nm ITO was cut to a size of 50 mm×50 mm×0.7 mm, ultrasonically washed with isopropyl alcohol for 5 minutes and then with pure water for 5 minutes, and washed again with UV ozone for 30 minutes, to prepare a first electrode. For top emission devices, the anode electrode was formed from 100 nm silver on glass which was prepared by the same methods as described above.

(22) Then, the hole injection layer, triarylamine compound and charge neutral metal amide compound according to the examples of Table 6 was vacuum co-deposited on the ITO electrode, to form a HIL having a thickness according to the examples 1 to 22 and comparative examples 1 to 5 of tables 6, 7 and 8. Then the corresponding hole injection layer according to the examples 1 to 22 and comparative examples 1 to 5 of tables 6, 7 and 8 was vacuum deposited on the HIL, to form a HTL having a thickness as mentioned in tables 6, 7 and 8, respectively.

(23) The wt.-% of the HIL-compound/s and HTL-compound according to the examples 1 to 22 and comparative examples 1 to 5 can be taken from Tables 6, 7 and 8 below, whereby the wt.-% amount of the HIL-compound/s is 100 wt.-% based on the total weight amount of the HIL-layer, and the wt.-% amount of the HTL-compound/s is 100 wt.-% based on the total weight amount of the HTL-layer, if no not indicated otherwise the wt.-% of the components are indicated in Tables 6, 7 and 8, respectively. That means that the HIL according to examples 1 to 22 consist of the triarylamine compound and metal amide compound according to the invention. However, the hole injection layer may comprises traces of the compound of the hole transport layer, due to the process of manufacture.

(24) 97 wt.-% of ABH113 (Sun Fine Chemicals) as a host and 3 wt.-% of NUBD370 (Sun Fine Chemicals) as a dopant were deposited on the HTL, to form a blue-emitting EML with a thickness of 20 nm.

(25) Then the ETL-layer of matrix compound of 50 wt.-% MX 2 and 50 wt.-% LiQ (50 wt.-%:50 wt.-%) having a thickness of 36 nm is formed by deposing the matrix compound from a first deposition source and the lithium organic complex or lithium halide from a second deposition source directly on the EML.

(26) For the comparative examples 1 to 5 and examples 1 to 22 only one electron transport layer is formed.

(27) The cathode was evaporated at ultra-high vacuum of 10.sup.−7 bar. Therefore, a thermal single co-evaporation of one or several metals was performed with a rate of 0, 1 to 10 nm/s (0.01 to 1 Å/s) in order to generate a homogeneous cathode with a thickness of 5 to 1000 nm. For top emission devices, the cathode electrode was formed from 13 nm magnesium (90 vol.-%)-silver (10 vol.-%) alloy. For bottom emission devices, the cathode electrode was formed from 100 nm aluminum.

(28) The OLED stack is protected from ambient conditions by encapsulation of the device with a glass slide. Thereby, a cavity is formed, which includes a getter material for further protection.

(29) To assess the performance of the inventive examples compared to the prior art, the current efficiency is measured under ambient conditions (20° C.). Current voltage measurements are performed using a Keithley 2400 sourcemeter, and recorded in V. At 10 mA/cm.sup.2 for bottom emission and 15 mA/cm.sup.2 for top emission devices, a calibrated spectrometer CAS140 from Instrument Systems is used for measurement of CIE coordinates and brightness in Candela. Lifetime LT of the device is measured at ambient conditions (20° C.) and 15 mA/cm.sup.2, using a Keithley 2400 sourcemeter, and recorded in hours. The brightness of the device is measured using a calibrated photo diode. The lifetime LT is defined as the time till the brightness of the device is reduced to 97% of its initial value.

(30) In bottom emission devices, the emission is predominately Lambertian and quantified in percent external quantum efficiency (EQE). To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode at 10 mA/cm.sup.2.

(31) In top emission devices, the emission is forward directed, non-Lambertian and also highly dependent on the mirco-cavity. Therefore, the efficiency EQE will be higher compared to bottom emission devices. To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode at 15 mA/cm.sup.2.

(32) Technical Effect of the Invention

(33) Effect of the Layer Thickness of the HIL on Device Performance without Cavity Control

(34) In order to test the performance of very thick hole injection layers (HIL), bottom emission OLED-devices are fabricated with a HIL thickness ranging from 100 nm to 450 nm. The HTL thickness is given in Table 6. The cavity, and thereby light out coupling, varies depending on HIL thickness, therefore no data are provided on efficiency EQE. In Table 6 the effect of the HIL thickness without cavity control is shown. As can be seen in Example 1 to 8, only a comparatively small increase in voltage is observed even for very thick layers.

(35) TABLE-US-00006 TABLE 6 Effect of HIL thickness on device performance without cavity control HIL dopant HIL HTL HIL dopant concentration thickness thickness U HIL compound [wt.-%] [nm] HTL [nm] [V] Example 1 T-3 Li(TFSI) 2 100 T-3 30 4.7 Example 2 T-3 Li(TFSI) 2 150 T-3 30 4.8 Example 3 T-3 Li(TFSI) 2 200 T-3 30 4.9 Example 4 T-3 Li(TFSI) 2 250 T-3 30 5 Example 5 T-3 Li(TFSI) 2 300 T-3 30 5 Example 6 T-3 Li(TFSI) 2 350 T-3 30 5.1 Example 7 T-3 Li(TFSI) 2 400 T-3 30 5.2 Example 8 T-3 Li(TFSI) 2 450 T-3 30 5.3
Effect of the Layer Thickness of the HIL on Device Performance at Constant Cavity

(36) In Table 7 is shown the effect of the HIL and HTL thickness on performance of bottom emission devices. The thickness of the layers is selected in such a way that the sum of the thickness of HIL and HTL is kept constant at 130 nm. Thereby, the cavity does not change and light outcoupling and efficiency EQE are not impacted.

(37) In comparative examples 1 and 2, the compound CNHAT (CAS 105598-27-4) has been used as a hole injection layer. In comparative example 1, a 10 nm layer of CNHAT was used. The efficiency EQE of 4.9% was obtained at a voltage of 5.4 V. However, it is desired to provide a thick HIL which can smooth over non-uniformities in the anode layer. Therefore, a 100 nm layer of CNHAT was tested. The efficiency EQE of 4.2% was achieved at 4.7 V.

(38) In summary, the efficiency EQE is reduced at thicknesses which would level out non-uniformities.

(39) Example 9 to 15 shows the effect of increased thickness of the HIL comprising triarylamine T-3 and metal amide Li(TFSI) on efficiency, voltage and voltage stability over time. As can be seen in Table 7, the efficiency is always higher than the efficiency obtained for devices containing a CNHAT HIL layer. Additionally, the efficiency EQE remains constant for a HIL thickness ranging from 20 to 120 nm. The voltage for a 20 nm HIL layer is slightly higher compared to the comparative examples but surprisingly, the voltage decreases to 4.8 to 4.9 V for thicker layers (example 10 to 15). The voltage stability of all examples is at an acceptable level, for example less than 0.35V over 50 hours stability test at 15 mA/cm.sup.2.

(40) TABLE-US-00007 TABLE 7 Effect of HIL thickness on device performance at constant cavity HIL dopant HIL HTL U(50 h)- HIL HIL dopant concentration thickness thickness U EQE U(0 h) compound compound [wt.-%] [nm] HTL [nm] [V] [%] [V] Comparative CNHAT 0 10 T-3 120 5.4 4.9 0.06 example 1 Comparative CNHAT 0 100 T-3 30 4.7 4.2 0.01 example 2 Example 9 T-3 Li(TFSI) 2 20 T-3 110 5.1 5.3 0.33 Example 10 T-3 Li(TFSI) 2 40 T-3 90 4.9 5.2 0.16 Example 11 T-3 Li(TFSI) 2 60 T-3 70 4.9 5.2 0.18 Example 12 T-3 Li(TFSI) 2 70 T-3 60 4.8 5.2 0.18 Example 13 T-3 Li(TFSI) 2 80 T-3 50 4.8 5.2 0.18 Example 14 T-3 Li(TFSI) 2 100 T-3 30 4.8 5.2 0.17 Example 15 T-3 Li(TFSI) 2 120 T-3 10 4.8 5.2 0.18
Effect of the Metal Cation on Device Performance

(41) In Table 8, the effect of the metal cation in the metal amide on performance of bottom emission devices. For ease of comparison, a 100 nm HIL was used in all examples. In Examples 16 to 20 are compared triarylamine T-3 doped with Li(TFSI), Ag(TFSI), Mg(TFSI).sub.2, Mn(TFSI).sub.2 and Li(cTFSI) (CAS 189217-62-7). The efficiency EQE is always higher than for comparative example 3 with CNHAT. Particularly high efficiency is obtained for a Ag(TFSI) doped HIL (example 18), while the lowest voltage and least voltage increase over time is achieved for Mg(TFSI) and Mn(TFSI).sub.2 (example 17 and 19, respectively).

(42) Effect of the HOMO Level of the Hole Transport Layer on Device Performance

(43) In order to achieve light output in different colours, a large variety of materials is available for application in the emission layer of OLEDs. Each emission layer composition comes with different demands on the HTL (for example band-gap or triplet level). Therefore, the HTL materials of different OLEDs may differ in their HOMO level. Consequently, a good hole injection layer enables hole injection in to a large variety of HTL materials.

(44) In a second step, triarylamine compounds with deeper HOMO levels are tested in the hole injection layer and hole transport layer, see Table 8. For ease of comparison, a 100 nm HIL was used in all examples. HTLs which show low performance with the fluorescent blue EML used here may show unique performance with a different EML composition, for example phosphorescent blue or green EML, or for TADF (thermally activated delayed fluorescence) emitters. In the following examples, the hole injection performance is evaluated relative to CNHAT which is not suitable for injection into deep HOMO HTLs. In comparative examples 4 and 5, CNHAT HIL is used together with deeper HOMO triarylamine compound T-8 (HOMO −5.25 eV) and T-9 (HOMO −5.33 eV). Compared to comparative example 3, where a triarylamine compound with a HOMO closer to vacuum level was used (T-3, HOMO −5.10 eV), the efficiency is slightly increased, however the voltage is so high, that a commercial application cannot be considered. As the voltage is very high, the voltage stability over time has not been measured. In example 21 and 22, the effect of a HIL comprising deep HOMO triarylamines and metal amide Mg(TFSI) is evaluated. As can be seen in Table 8, the efficiency is significantly higher than for CNHAT HIL and the voltage is significantly lower (5.2 compared to 6.1 V and 6.2 compared to 8.6 V, respectively). In summary, a wide range of metal amides with various metal cations can be successfully used as HIL dopant. Additionally, both open-chain and cyclic amide ligands show the desired effect (Li(TFSI) compared to Li(cTFSI), example 16 and 20, respectively). Furthermore, the invention is particularly useful for efficient hole injection into deeper HOMO HTLs which are required for OLEDs which rely on phosphorescent or TADF emitters, in particular green and blue emitters.

(45) TABLE-US-00008 TABLE 8 Effect of metal cation and HOMO level of HTL on device performance HIL dopant HIL U(50 h)- HIL HIL dopant concentration Thickness U EQE U(0 h) compound compound [wt.-%] [nm] HTL [V] [%] [V] Comparative CNHAT — 0 100 T-3 4.7 4.2 0.01 example 3 Comparative CNHAT — 0 100 T-8 6.1 4.5 — example 4 Comparative CNHAT — 0 100 T-9 8.6 4.9 — example 5 Example 16 T-3 Li(TFSI) 2 100 T-3 4.8 5.2 0.17 Example 17 T-3 Mg(TFSI).sub.2 2 100 T-3 4.8 5.1 0.02 Example 18 T-3 Ag(TFSI) 2 100 T-3 5.6 5.3 0.2 Example 19 T-3 Mn(TFSI).sub.2 2 100 T-3 4.7 4.7 0.14 Example 20 T-3 Li(cTFSI) 2 100 T-3 4.8 4.9 0.15 Example 21 T-8 Mg(TFSI).sub.2 2 100 T-8 5.2 5.3 0.1 Example 22 T-9 Mg(TFSI).sub.2 2 100 T-9 6.2 5.3 0.25

(46) Another aspect is directed to an organic light-emitting diode (OLED) comprising more than one emission layer (EML) 150, for example two, three or four emission layers may be present. An organic light-emitting diode (OLED) comprising more than one emission layer is also described as a tandem OLED or stacked OLED.

(47) Another aspect is directed to a device comprising at least one organic light-emitting diode (OLED). A device comprising organic light-emitting diodes (OLED) is for example a display or a lighting panel.

(48) From the foregoing detailed description and examples, it will be evident that modifications and variations can be made to the compositions and methods of the invention without departing from the spirit and scope of the invention. Therefore, it is intended that all modifications made to the invention without departing from the spirit and scope of the invention come within the scope of the appended claims.