ELECTRONIC DEVICE

Abstract

The application relates to an electronic device comprising an organic layer containing a mixture of at least two different compounds.

Claims

1.-22. (canceled)

23. An electronic device comprising anode, cathode, emitting layer disposed between anode and cathode, a hole injection layer disposed between anode and emitting layer; a hole-transporting layer disposed between hole injection layer and emitting layer and directly adjoining the emitting layer on the anode side, and containing two different compounds conforming to identical or different formulae selected from formulae (I) and (II) ##STR00175## where Z is the same or different at each instance and is selected from CR.sup.1 and N, where Z is C when a ##STR00176##  group is bonded thereto; X is the same or different at each instance and is selected from the group consisting of a single bond, O, S, C(R.sup.1).sub.2 and NR.sup.1; Ar.sup.1 and Ar.sup.2 are the same or different at each instance and are selected from aromatic ring systems which have 6 to 40 aromatic ring atoms and are substituted by one or more R.sup.2 radicals and heteroaromatic ring systems which have 5 to 40 aromatic ring atoms and are substituted by one or more R.sup.2 radicals; R.sup.1 and R.sup.2 are the same or different at each instance and are selected from H, D, F, Cl, Br, I, C(═O)R.sup.3, CN, Si(R.sup.3).sub.3, N(R.sup.3).sub.2, P(═O)(R.sup.3).sub.2, OR.sup.3, S(═O)R.sup.3, S(═O).sub.2R.sup.3, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R.sup.1 or R.sup.2 radicals may be joined to one another and may form a ring; where the alkyl, alkoxy, alkenyl and alkynyl groups mentioned and the aromatic ring systems and heteroaromatic ring systems mentioned are each substituted by R.sup.3 radicals; and where one or more CH.sub.2 groups in the alkyl, alkoxy, alkenyl and alkynyl groups mentioned may be replaced by —R.sup.3C═CR.sup.3—, —C≡C—, Si(R.sup.3).sub.2, C═O, C═NR.sup.3, —C(═O)O—, —C(═O)NR.sup.3—, NR.sup.3, P(═O)(R.sup.3), —O—, —S—, SO or SO.sub.2; R.sup.3 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, CN, alkyl or alkoxy groups having 1 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R.sup.3 radicals may be joined to one another and may form a ring; and where the alkyl, alkoxy, alkenyl and alkynyl groups, aromatic ring systems and heteroaromatic ring systems mentioned may be substituted by one or more radicals selected from F and CN; n is 0, 1, 2, 3 or 4, where, when n=0, the Ar.sup.1 group is absent and the nitrogen atom is bonded directly to the rest of the formula.

24. The electronic device according to claim 23, wherein the emitting layer is a blue-fluorescing emitting layer or a green-phosphorescing emitting layer.

25. The electronic device according to claim 23, wherein the hole-transporting layer has a layer thickness of 20 nm to 300 nm.

26. The electronic device according to claim 23, wherein the hole-transporting layer has a layer thickness of not more than 250 nm.

27. The electronic device according to claim 23, wherein the hole-transporting layer contains exactly 2 different compounds conforming to identical or different formulae selected from formulae (I) and (II).

28. The electronic device according to claim 23, wherein the hole-transporting layer consists of compounds conforming to identical or different formulae selected from formulae (I) and (II).

29. The electronic device according to claim 23, wherein the hole-transporting layer contains two different compounds conforming to a formula (I).

30. The electronic device according to claim 23, wherein the two different compounds conforming to identical or different formulae selected from formulae (I) and (II) are each present in the hole-transporting layer in a proportion of at least 5%.

31. The electronic device according to claim 23, wherein one of the two different compounds in the hole-transporting layer is a compound HTM-1 selected from formulae (I-1-A) and (II-1-A) ##STR00177## and the other of the two different compounds in the hole-transporting layer is a compound HTM-2 selected from the formulae (I-1-B), (I-1-C), (I-1-D), (II-1-B), (II-1-C), and (II-1-D) ##STR00178## where the groups that occur in the formulae (I-1-A) to (I-1-D) and (II-1-B) to (II-1-D) are as defined in claim 23, and where the unoccupied positions on the spirobifluorene and fluorene are each substituted by R.sup.1 radicals.

32. The electronic device according to claim 31, wherein HTM-1 is present in the hole-transporting layer in a proportion five to two times as high as the proportion of HTM-2 in the hole-transporting layer.

33. The electronic device according to claim 31, wherein HTM-1 is present in the hole-transporting layer in a proportion of 65% to 85%, and HTM-2 in the hole-transporting layer in a proportion of 15% to 35%.

34. The electronic device according to claim 31, wherein HTM-1 has a HOMO of −4.8 eV to −5.2 eV, and HTM-2 a HOMO of −5.1 eV to −5.4 eV.

35. The electronic device according to claim 31, wherein HTM-1 has a HOMO higher than HTM-2 by 0.02 eV to 0.3 eV.

36. The electronic device according to claim 23, wherein the electronic device has the layer sequence anode/hole injection layer/hole-transporting layer/emitting layer, where the layers mentioned directly adjoin one another.

37. The electronic device according to claim 23, wherein the hole injection layer contains a mixture of a p-dopant and a hole transport material.

38. The electronic device according to claim 23, wherein the hole transport material of the hole injection layer is selected from the compounds of the formulae (I-1-A) or (II-1-A), ##STR00179## where groups that occur in the formulae (I-1-A) and (II-1-A) are as defined in claim 23, and where the unoccupied positions on the spirobifluorene and fluorene are each substituted by R.sup.1 radicals.

39. The electronic device according to claim 23, wherein the hole injection layer contains a hexaazatriphenylene derivative or another highly electron-deficient and/or Lewis-acidic compound, each in pure form.

40. Process for producing the electronic device according to claim 23, wherein one or more layers of the device are produced from solution or by a sublimation process.

41. A device in displays, as a light source in lighting applications or as a light source in medical and/or cosmetic applications which comprises the electronic device according to claim 23.

42. The compound of one of the following structural formulae H-1 to H-130: ##STR00180## ##STR00181## ##STR00182## ##STR00183## ##STR00184## ##STR00185## ##STR00186## ##STR00187## ##STR00188## ##STR00189## ##STR00190## ##STR00191## ##STR00192## ##STR00193## ##STR00194## ##STR00195## ##STR00196## ##STR00197## ##STR00198## ##STR00199## ##STR00200## ##STR00201## ##STR00202## ##STR00203##

43. An organic electroluminescent device comprising the compound according to claim 42.

44. The organic electroluminescent device according to claim 43, wherein the compound is in a hole-transporting layer and/or in an emitting layer as matrix material.

45. An organic electroluminescent device comprising the compound according to claim 42, wherein the compound is in a hole injection layer, a hole transport layer, an electron blocker layer and/or an emitting layer.

Description

EXAMPLES

1) General Production Process for the OLEDs and Characterization of the OLEDs

[0129] Glass plaques which have been coated with structured ITO (indium tin oxide) in a thickness of 50 nm are the substrates to which the OLEDs are applied.

[0130] The OLEDs basically have the following layer structure: substrate/hole injection layer (HIL)/hole transport layer (HTL)/emission layer (EML)/electron transport layer (ETL)/electron injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer of thickness 100 nm. The exact structure of the OLEDs can be found in the Tables 1.

[0131] All materials are applied by thermal vapour deposition in a vacuum chamber. The emission layer here, in the present examples, consists of a matrix material (host material) and an emitting dopant (emitter) which is added to the matrix material in a particular proportion by volume by co-evaporation. Details given in such a form as SMB1:SEB1 (5%) mean here that the material SMB1 is present in the layer in a proportion by volume of 95% and the material SEB1 in a proportion by volume of 5%. Analogously, the electron transport layer and, in particular examples, the HIL and/or the HTL as well also consist of a mixture of two materials, where the proportions of the materials are reported as specified above.

[0132] The chemical structures of the materials that are used in the OLEDs are shown in Table 2.

[0133] The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, the external quantum efficiency (EQE, measured in %) as a function of the luminance, calculated from current-voltage-luminance characteristics assuming Lambertian radiation characteristics, and the lifetime are determined. The parameter EQE @ 10 mA/cm.sup.2 refers to the external quantum efficiency which is attained at 10 mA/cm.sup.2. The parameter U @ 10 mA/cm.sup.2 refers to the operating voltage at 10 mA/cm.sup.2. The lifetime LT is defined as the time after which the luminance drops from the starting luminance to a certain proportion in the course of operation with constant current density. An LT80 figure means here that the lifetime reported corresponds to the time after which the luminance has dropped to 80% of its starting value. The figure @60 mA/cm.sup.2 means here that the lifetime in question is measured at 60 mA/cm.sup.2.

2) OLEDs with a Mixture of Two Different Materials in the HTL and Comparative Examples with a Single Material in HTL, with p-Doped HIL

[0134] The following OLEDs are produced:

TABLE-US-00001 TABLE 1A Ex. HIL HTL1 EML ETL EIL Thickness/ Thickness/nm Thickness/nm Thickness/nm Thickness/ nm nm C1 HTM3: HTM3 SMB1:SEB1 (5%) ETM:LiQ(50%) LiQ PDM(5%) 200 nm 20 nm 30 nm 1 nm 20 nm I1 HTM3: HTM3:HTM5(20%) SMB1:SEB1 (5%) ETM:LiQ(50%) LiQ PDM(5%) 200 nm 20 nm 30 nm 1 nm 20 nm C2 HTM2: HTM2 SMB1:SEB1 (5%) ETM:LiQ(50%) LiQ PDM(5%) 200 nm 20 nm 30 nm 1 nm 20 nm I2 HTM2: HTM2:HTM6(20%) SMB1:SEB1 (5%) ETM:LiQ(50%) LiQ PDM(5%) 200 nm 20 nm 30 nm 1 nm 20 nm

[0135] This gives the following measurement data:

TABLE-US-00002 U EQE @ 10 mA/cm.sup.2 @ 10 mA/cm.sup.2 [V] [%] C1 3.8 8.8 I1 3.8 9.2 C2 4.3 9.7 I2 4.5 9.9

[0136] By addition of the compound HTM5 to the HTL containing HTM3, a distinct improvement in efficiency is achieved in OLED 11 at the same voltage. The comparison is made here with the OLED C1 that contains exclusively the compound HTM3 in the HTL, and is otherwise of the same construction.

[0137] A distinct improvement in efficiency is also found when the compound HTM6 is added to the HTL containing HTM2 (OLED 12). The comparison is made here with the OLED C2 that contains exclusively the compound HTM2 in the HTL, and is otherwise of the same construction.

[0138] Even though the improvements in efficiency are small in percentage terms, they are not negligible since improvements in efficiency are difficult to achieve.

3) OLEDs with a Mixture of Two Different Materials in the HTL and Comparative Examples with a Single Material in HTL, with HIL Composed of a Single Material

[0139] The following OLEDs are produced:

TABLE-US-00003 TABLE 1B Ex. HIL HTL1 EML ETL EIL Thickness/ Thickness/nm Thickness/nm Thickness/nm Thickness/ nm nm C3 HIL1 HTM1 SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 200 nm 20 nm 30 nm 1 nm I3 HIL1 HTM1:HTM5(20%) SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 200 nm 20 nm 30 nm 1 nm I4 HIL1 HTM1:HTM6(20%) SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 200 nm 20 nm 30 nm 1 nm

[0140] This gives the following measurement data:

TABLE-US-00004 U @ 10 mA/cm.sup.2 LT80 @ 60 mA/cm.sup.2 [V] [h] C3 3.8 285 I3 3.8 311 I4 3.8 293

[0141] By addition of the compounds HTM5 (13) or HTM6 (14) to the HTL containing the compound HTM1, an improvement in lifetime is achieved in each case. The comparison is made here with the OLED C3 that contains exclusively the compound HTM1 in the HTL, and is otherwise of the same construction.

[0142] In the case of OLEDs that have a thinner HTL (70 nm) compared to the thicker HTL that is used in the OLEDs C3, 13 and 14, improvements in lifetime likewise occur, as shown by the examples that follow. As before, OLEDs with a mixture of two different materials in the HTL (16, 17 and 18) are compared here with an OLED containing exclusively the compound HTM1 in the HTL (C4).

TABLE-US-00005 TABLE 1C Ex. HIL HTL1 EML ETL EIL Thickness/ Thickness/nm Thickness/nm Thickness/nm Thickness/ nm nm C4 HIL1 HTM1 SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 70 nm 20 nm 30 nm 1 nm I6 HIL1 HTM1:HTM7(20%) SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 70 nm 20 nm 30 nm 1 nm I7 HIL1 HTM1:HTM6(20%) SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 70 nm 20 nm 30 nm 1 nm I8 HIL1 HTM1:HTM5(20%) SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 70 nm 20 nm 30 nm 1 nm

[0143] This gives the following measurement data:

TABLE-US-00006 U @ 10 mA/cm.sup.2 LT80 @ 60 mA/cm.sup.2 [V] [h] C4 3.6 285 I6 3.5 308 I7 3.6 310 I8 3.5 306

[0144] In all cases, addition of a material selected from HTM5, HTM6 and HTM7 improves the lifetime of the OLED.

[0145] The second material may also be added in a higher proportion than in the 20% shown above, as shown by the following example:

TABLE-US-00007 TABLE 1D Ex. HIL HTL1 EML ETL EIL Thickness/ Thickness/nm Thickness/nm Thickness/nm Thickness/ nm nm C4 HIL1 HTM1 SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 70 nm 20 nm 30 nm 1 nm I5 HIL1 HTM1:HTM5(50%) SMB1:SEB1(5%) ETM:LiQ(50%) LiQ 5 nm 70 nm 20 nm 30 nm 1 nm

[0146] The following results are obtained:

TABLE-US-00008 U @ 10 mA/cm.sup.2 LT80 @ 60 mA/cm.sup.2 [V] [h] C4 3.6 285 I5 3.6 353

[0147] However, the addition of the second material in a high proportion has the disadvantage that losses in efficiency occur. When the second material is used in a proportion of 10-30% by volume, especially 20% by volume, as shown above, these occur to a distinctly lesser degree, if at all.

TABLE-US-00009 TABLE 2 [00163] HIL1 [00164] PDM [00165] SMB1 [00166] SEB1 [00167] ETM [00168] LiQ [00169] HTM1 [00170] HTM2 [00171] HTM3 [00172] HTM5 [00173] HTM6 [00174] HTM7
4) Determination of the HOMO of the Compounds that are Used in the Mixed HTL

[0148] The method described at page 28 line 1 to page 29 line 21 of published specification WO 2011/032624 gives the following values for the HOMO of the compounds HTM1, HTM2, HTM3, HTM5, HTM6 and HTM7:

TABLE-US-00010 Compound HOMO (eV) HTM1 −5.15 HTM2 −5.18 HTM3 −5.15 HTM5 −5.27 HTM6 −5.23 HTM7 −5.26