ORGANIC ELECTROLUMINESCENT DEVICE

Abstract

The present invention relates to organic electroluminescent devices comprising a light-emitting layer B comprising a triplet-triplet annihilation (TTA) material, a thermally activated delayed fluorescence (TADF) material and a near-range-charge-transfer (NRCT) emitter material, which exhibits a narrow—expressed by a small full width at half maximum (FWHM)—emission. Further, the present invention relates to a method for obtaining a desired light spectrum and achieving suitable (long) lifespans of an organic electroluminescent device according to the present invention.

Claims

1. An organic electroluminescent device comprising a light-emitting layer B comprising: (i) a first compound H.sup.N, which has a lowermost excited singlet state energy level S1.sup.N, a lowermost excited triplet state energy level T1.sup.N, (ii) a second compound E.sup.B, which has a lowermost excited singlet state energy level S1.sup.E and a lowermost excited triplet state energy level T1.sup.E, and (iii) a third compound S.sup.B, which has a lowermost excited singlet state energy level S1.sup.S and a lowermost excited triplet state energy level T1.sup.S wherein the relations expressed by the following formulas (1) to (3) apply:
S1.sup.E>S1.sup.S (1)
S1.sup.N>S1.sup.S (2)
S1.sup.S<2.95 eV (3).

2. The organic electroluminescent device according to claim 1, wherein the second compound E.sup.B exhibits a ΔE.sub.ST value, which corresponds to the energy difference between the lowermost excited singlet state (S1) and the lowermost excited triplet state (T1), of less than 0.4 eV; and wherein the third compound S.sup.B exhibits an emission with a full width at half maximum (FWHM) below 0.35 eV, in PMMA with 5% by weight of the third compound S.sup.B.

3. The organic electroluminescent device according to claim 1, wherein said organic electroluminescent device is a device selected from the group consisting of an organic light emitting diode, a light emitting electrochemical cell, and a light-emitting transistor.

4. The organic electroluminescent device according to claim 1, wherein the second compound E.sup.B is an organic TADF material.

5. The organic electroluminescent device according to claim 1, wherein the device exhibits an emission maximum λ.sub.max(D) of 440 to 475 nm.

6. The organic electroluminescent device according to claim 1, wherein the light-emitting layer B comprises: (i) 10-96.5% by weight of the first compound H.sup.N; (ii) 3-50% by weight of the second compound E.sup.B; and (iii) 0.5-30% by weight of the third compound S.sup.B; and (iv) optionally 0-74% by weight of one or more solvents.

7. The organic electroluminescent device according to claim 1, wherein the light-emitting layer B comprises: (i) 40-74% by weight of the first compound H.sup.N; (ii) 15-30% by weight of the second compound E.sup.B; and (iii) 1-5% by weight of the third compound S.sup.B; and (iv) optionally 0-34% by weight of one or more solvents.

8. The organic electroluminescent device according to claim 1, wherein the first compound H.sup.N is an anthracene derivative.

9. The organic electroluminescent device according to claim 1, wherein the third compound S.sup.B comprises a structure according to Formula I-NRCT: ##STR00221## wherein is 0 or 1; m=1-o; X.sup.1 is N or B; X.sup.2 is N or B; X.sup.3 is N or B; W is selected from the group consisting of Si(R.sup.3S).sub.2, C(R.sup.3S).sub.2 and BR.sup.3S; each of R.sup.1S, R.sup.2S and R.sup.3S is independently selected from the group consisting of: C.sub.1-C.sub.5-alkyl, which is optionally substituted with one or more substituents R.sup.6S; C.sub.6-C.sub.60-aryl, which is optionally substituted with one or more substituents R.sup.6S; and C.sub.3-C.sub.57-heteroaryl, which is optionally substituted with one or more substituents R.sup.6S; each of R.sup.I, R.sup.II, R.sup.III, R.sup.IV, R.sup.V, R.sup.VI, R.sup.VII, R.sup.VIII, R.sup.IX, R.sup.X, and R.sup.XI is independently selected from the group consisting of: hydrogen, deuterium, N(R.sup.5S).sub.2, OR.sup.5S, Si(R.sup.5S).sub.3, B(OR.sup.5S).sub.2, OSO.sub.2R.sup.5S, CF.sub.3, CN, halogen, C.sub.1-C.sub.40-alkyl, which is optionally substituted with one or more substituents R.sup.5S and wherein one or more non-adjacent CH.sub.2-groups are each optionally substituted by R.sup.5SC═CR.sup.5S, C≡C, Si(R.sup.5S).sub.2, Ge(R.sup.5S).sub.2, Sn(R.sup.5S).sub.2, C═O, C═S, C═Se, C═NR.sup.5S, P(═O)(R.sup.5S), SO, SO.sub.2, NR.sup.5S, O, S or CONR.sup.5S; C.sub.1-C.sub.40-alkoxy, which is optionally substituted with one or more substituents R.sup.5S and wherein one or more non-adjacent CH.sub.2-groups are each optionally substituted by R.sup.5SC═CR.sup.5S, C≡C, Si(R.sup.5S).sub.2, Ge(R.sup.5S).sub.2, Sn(R.sup.5S).sub.2, C═O, C═S, C═Se, C═NR.sup.5S, P(═O)(R.sup.5S), SO, SO.sub.2, NR.sup.5S, O, S or CONR.sup.5S; C.sub.1-C.sub.40-thioalkoxy, which is optionally substituted with one or more substituents R.sup.5S and wherein one or more non-adjacent CH.sub.2-groups are each optionally substituted by R.sup.5SC═CR.sup.5S, C≡C, Si(R.sup.5S).sub.2, Ge(R.sup.5S).sub.2, Sn(R.sup.5S).sub.2, C═O, C═S, C═Se, C═NR.sup.5S, P(═O)(R.sup.5S), SO, SO.sub.2, NR.sup.5S, O, S or CONR.sup.5S; C.sub.2-C.sub.40-alkenyl, which is optionally substituted with one or more substituents R.sup.5S and wherein one or more non-adjacent CH.sub.2-groups are each optionally substituted by R.sup.5SC═CR.sup.5S, C≡C, Si(R.sup.5S).sub.2, Ge(R.sup.5S).sub.2, Sn(R.sup.5S).sub.2, C═O, C═S, C═Se, C═NR.sup.5S, P(═O)(R.sup.5S), SO, SO.sub.2, NR.sup.5S, O, S or CONR.sup.5S; C.sub.2-C.sub.40-alkynyl, which is optionally substituted with one or more substituents R.sup.5S and wherein one or more non-adjacent CH.sub.2-groups are each optionally substituted by R.sup.5SC═CR.sup.5S, C≡C, Si(R.sup.5S).sub.2, Ge(R.sup.5S).sub.2, Sn(R.sup.5S).sub.2, C═O, C═S, C═Se, C═NR.sup.5S, P(═O)(R.sup.5S), SO, SO.sub.2, NR.sup.5S, O, S or CONR.sup.5S; C.sub.6-C.sub.60-aryl, which is optionally substituted with one or more substituents R.sup.5S; and C.sub.3-C.sub.57-heteroaryl, which is optionally substituted with one or more substituents R.sup.5S; R.sup.5S is at each occurrence independently from another selected from the group consisting of: hydrogen, deuterium, OPh, CF.sub.3, CN, F, C.sub.1-C.sub.5-alkyl, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.1-C.sub.5-alkoxy, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.1-C.sub.5-thioalkoxy, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.2-C.sub.5-alkenyl, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.2-C.sub.5-alkynyl, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.6-C.sub.18-aryl, which is optionally substituted with one or more C.sub.1-C.sub.5-alkyl substituents; C.sub.3-C.sub.17-heteroaryl, which is optionally substituted with one or more C.sub.1-C.sub.5-alkyl substituents; N(C.sub.6-C.sub.18-aryl).sub.2, N(C.sub.3-C.sub.17-heteroaryl).sub.2; and N(C.sub.3-C.sub.17-heteroaryl)(C.sub.6-C.sub.18-aryl); R.sup.6S is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, OPh, CF.sub.3, CN, F, C.sub.1-C.sub.5-alkyl, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.1-C.sub.5-alkoxy, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.1-C.sub.5-thioalkoxy, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.2-C.sub.5-alkenyl, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.2-C.sub.5-alkynyl, wherein optionally one or more hydrogen atoms are independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.6-C.sub.18-aryl, which is optionally substituted with one or more C.sub.1-C.sub.5-alkyl substituents; C.sub.3-C.sub.17-heteroaryl, which is optionally substituted with one or more C.sub.1-C.sub.5-alkyl substituents; N(C.sub.6-C.sub.18-aryl).sub.2, N(C.sub.3-C.sub.17-heteroaryl).sub.2; and N(C.sub.3-C.sub.17-heteroaryl)(C.sub.6-C.sub.18-aryl); wherein two or more of the substituents selected from the group consisting of R.sup.I, R.sup.II, R.sup.III, R.sup.IV, R.sup.V, R.sup.VI, R.sup.VII, R.sup.VIII, R.sup.IX, R.sup.X, and R.sup.XI that are positioned adjacent to another may optionally each form a ring system with another, wherein the ring system is selected from the group consisting of mono- or polycyclic ring system, aliphatic ring system, aromatic ring system, benzo-fused ring system and combinations thereof; and wherein at least one of X.sup.1, X.sup.2 and X.sup.3 is B and at least one of X.sup.1, X.sup.2 and X.sup.3 is N.

10. The organic electroluminescent device according to claim 9, wherein X.sup.1 and X.sup.3 each are N and X.sup.2 is B.

11. The organic electroluminescent device according to claim 9, wherein X.sup.1 and X.sup.3 each are B and X.sup.2 is N.

12. The organic electroluminescent device according to claim 9, wherein o=0.

13. The organic electroluminescent device according to claim 9, wherein each of R.sup.I, R.sup.II, R.sup.III, R.sup.IV, R.sup.V, R.sup.VI, R.sup.VII, R.sup.VIII, R.sup.IX, R.sup.X, and R.sup.XI is independently selected from the group consisting of: hydrogen, deuterium, halogen, Me, .sup.iPr, .sup.tBu, CN, CF.sub.3, Ph, which is optionally substituted with one or more substituents independently selected from the group consisting of Me, .sup.iPr, .sup.tBu, CN, CF.sub.3, and Ph, pyridinyl, which is optionally substituted with one or more substituents independently selected from the group consisting of Me, .sup.iPr, .sup.tBu, CN, CF.sub.3, and Ph, pyrimidinyl, which is optionally substituted with one or more substituents independently selected from the group consisting of Me, .sup.iPr, .sup.tBu, CN, CF.sub.3, and Ph, carbazolyl, which is optionally substituted with one or more substituents independently selected from the group consisting of Me, .sup.iPr, .sup.tBu, CN, CF.sub.3, and Ph, triazinyl, which is optionally substituted with one or more substituents independently selected from the group consisting of Me, .sup.iPr, .sup.tBu, CN, CF.sub.3, and Ph, and N(Ph).sub.2; and R.sup.1S and R.sup.2S are each independently selected from the group consisting of C.sub.1-C.sub.5-alkyl, which is optionally substituted with one or more substituents R.sup.6S; C.sub.6-C.sub.30-aryl, which is optionally substituted with one or more substituents R.sup.6S; and C.sub.3-C.sub.30-heteroaryl, which is optionally substituted with one or more substituents R.sup.6S.

14. The organic electroluminescent device according to claim 1, wherein the device exhibits an emission maximum λ.sub.max(D) of 450 to 470 nm.

15. The organic electroluminescent device according to claim 1, wherein the second compound E.sup.B is a carbazole derivative.

16. The organic electroluminescent device according to claim 1, wherein the second compound E.sup.B comprises a structure according to Formula I-TADF: ##STR00222## wherein n is 1 or 2; X is selected from the group of Ar.sup.EWG, CN or CF.sub.3; Z is selected from the group of a direct bond, CR.sup.3R.sup.4, C═CR.sup.3R.sup.4, C═O, C═NR.sup.3, NR.sup.3, O, SiR.sup.3R.sup.4, S, S(O) and S(O).sub.2; Ar.sup.EWG is selected from one of Formulas IIa to IIk; ##STR00223## ##STR00224## wherein # represents the binding site of the single bond linking Ar.sup.EWG to the substituted central phenyl ring of Formula I-TADF; each of R.sup.1 and R.sup.2 is independently from another selected from the group consisting of hydrogen, deuterium, C.sub.1-C.sub.5-alkyl, wherein one or more hydrogen atoms are optionally substituted by deuterium, and C.sub.6-C.sub.18-aryl, which is optionally substituted with one or more substituents R.sup.6; each of R.sup.a, R.sup.3 and R.sup.4 is independently from another selected from the group consisting of: hydrogen, deuterium, N(R.sup.5).sub.2, OR.sup.5, SR.sup.5, Si(R.sup.5).sub.3, CF.sub.3, CN, F, C.sub.1-C.sub.40-alkyl, which is optionally substituted with one or more substituents R.sup.5 and wherein one or more non-adjacent CH.sub.2-groups are optionally substituted by R.sup.5C═CR.sup.5, C≡C, Si(R.sup.5).sub.2, Ge(R.sup.5).sub.2, Sn(R.sup.5).sub.2, C═O, C═S, C═Se, C═NR.sup.5, P(═O)(R.sup.5), SO, SO.sub.2, NR.sup.5, O, S or CONR.sup.5; C.sub.1-C.sub.40-thioalkoxy, which is optionally substituted with one or more substituents R.sup.5 and wherein one or more non-adjacent CH.sub.2-groups are optionally substituted by R.sup.5C═CR.sup.5, C≡C, Si(R.sup.5).sub.2, Ge(R.sup.5).sub.2, Sn(R.sup.5).sub.2, C═O, C═S, C═Se, C═NR.sup.5, P(═O)(R.sup.5), SO, SO.sub.2, NR.sup.5, O, S or CONR.sup.5; and C.sub.6-C.sub.60-aryl, which is optionally substituted with one or more substituents R.sup.5; C.sub.3-C.sub.57-heteroaryl which is optionally substituted with one or more substituents R.sup.5; R.sup.5 is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R.sup.6).sub.2, OR.sup.6, SR.sup.6, Si(R.sup.6).sub.3, CF.sub.3, CN, F, C.sub.1-C.sub.40-alkyl, which is optionally substituted with one or more substituents R.sup.6 and wherein one or more non-adjacent CH.sub.2-groups are optionally substituted by R.sup.6C═CR.sup.6, C≡C, Si(R.sup.6).sub.2, Ge(R.sup.6).sub.2, Sn(R.sup.6).sub.2, C═O, C═S, C═Se, C═NR.sup.6, P(═O)(R.sup.6), SO, SO.sub.2, NR.sup.6, O, S or CONR.sup.6; C.sub.6-C.sub.60-aryl, which is optionally substituted with one or more substituents R.sup.6; and C.sub.3-C.sub.57-heteroaryl, which is optionally substituted with one or more substituents R.sup.6; R.sup.6 is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, OPh, CF.sub.3, CN, F, C.sub.1-C.sub.5-alkyl, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.1-C.sub.5-alkoxy, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.1-C.sub.5-thioalkoxy, wherein one or more hydrogen atoms are optionally, independently from each other substituted by deuterium, CN, CF.sub.3, or F; C.sub.6-C.sub.18-aryl, which is optionally substituted with one or more C.sub.1-C.sub.5-alkyl substituents; C.sub.3-C.sub.17-heteroaryl, which is optionally substituted with one or more C.sub.1-C.sub.5-alkyl substituents; N(C.sub.6-C.sub.18-aryl).sub.2; N(C.sub.3-C.sub.17-heteroaryl).sub.2, and N(C.sub.3-C.sub.12-heteroaryl)(C.sub.6-C.sub.18-aryl); R.sup.d is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, N(R.sup.5).sub.2, OR.sup.S, SR.sup.S, Si(R.sup.5).sub.3, CF.sub.3, CN, F, C.sub.1-C.sub.40-alkyl, which is optionally substituted with one or more substituents R.sup.5 and wherein one or more non-adjacent CH.sub.2-groups are optionally substituted by R.sup.5C═CR.sup.5, C≡C, Si(R.sup.5).sub.2, Ge(R.sup.5).sub.2, Sn(R.sup.5).sub.2, C═O, C═S, C═Se, C═NR.sup.5, P(═O)(R.sup.5), SO, SO.sub.2, NR.sup.5, O, S or CONR.sup.5; C.sub.1-C.sub.40-thioalkoxy, which is optionally substituted with one or more substituents R.sup.5 and wherein one or more non-adjacent CH.sub.2-groups are optionally substituted by R.sup.5C═CR.sup.5, C≡C, Si(R.sup.5).sub.2, Ge(R.sup.5).sub.2, Sn(R.sup.5).sub.2, C═O, C═S, C═Se, C═NR.sup.5, P(═O)(R.sup.5), SO, SO.sub.2, NR.sup.5, O, S or CONR.sup.5; and C.sub.6-C.sub.60-aryl, which is optionally substituted with one or more substituents R.sup.5; C.sub.3-C.sub.57-heteroaryl which is optionally substituted with one or more substituents R.sup.5; wherein the substituents R.sup.a, R.sup.3, R.sup.4 or R.sup.5 independently from each other optionally may form a mono- or polycyclic, aliphatic, aromatic and/or benzo-fused ring system with one or more substituents R.sup.a, R.sup.3, R.sup.4 or R.sup.5 and wherein the one or more substituents R.sup.d independently from each other optionally may form a mono- or polycyclic, aliphatic, aromatic and/or benzo-fused ring system with one or more substituents R.sup.d.

17. The organic electroluminescent device according to claim 1, wherein the device exhibits a CIEx color coordinate of between 0.02 and 0.30 and/or a CIEy color coordinate of between 0.00 and 0.45.

18. The organic electroluminescent device according to claim 1, wherein the second compound E.sup.B and the third compound S.sup.B are both organic materials.

Description

EXAMPLES

Cyclic Voltammetry

[0378] Cyclic voltammograms of solutions having concentration of 10.sup.−3 mol/l of the organic molecules in dichloromethane or a suitable solvent and a suitable supporting electrolyte (e.g. 0.1 mol/l of tetrabutylammonium hexafluorophosphate) are measured. The measurements are conducted at room temperature and under nitrogen atmosphere with a three-electrode assembly (Working and counter electrodes: Pt wire, reference electrode: Pt wire) and calibrated using FeCp.sub.2/FeCp.sub.2.sub.+ as internal standard. HOMO data was corrected using ferrocene as internal standard against SCE.

Density Functional Theory Calculation

[0379] Molecular structures are optimized employing the BP86 functional and the resolution of identity approach (RI). Excitation energies are calculated using the (BP86) optimized structures employing Time-Dependent DFT (TD-DFT) methods. Orbital and excited state energies are calculated with the B3LYP functional. Def2-SVP basis sets (and a m4-grid for numerical integration were used. The Turbomole program package was used for all calculations.

Photophysical Measurements

[0380] Sample pretreatment: Spin-coating
Apparatus: Spin150, SPS euro.

[0381] The sample concentration is 10 mg/ml, dissolved in a suitable solvent.

Program: 1) 3 s at 400 U/min; 20 s at 1000 U/min at 1000 Upm/s. 3) 10 s at 4000 U/min at 1000 Upm/s. After coating, the films are tried at 70° C. for 1 min.
Photoluminescence spectroscopy and TCSPC (Time-correlated single-photon counting) Steady-state emission spectroscopy is recorded using a Horiba Scientific, Modell FluoroMax-4 equipped with a 150 W Xenon-Arc lamp, excitation- and emissions monochromators and a Hamamatsu R928 photomultiplier and a time-correlated single-photon counting option. Emissions and excitation spectra are corrected using standard correction fits.

[0382] Excited state lifetimes are determined employing the same system using the TCSPC method with FM-2013 equipment and a Horiba Yvon TCSPC hub.

Excitation Sources:

[0383] NanoLED 370 (wavelength: 371 nm, puls duration: 1.1 ns)
NanoLED 290 (wavelength: 294 nm, puls duration: <1 ns)
SpectraLED 310 (wavelength: 314 nm)
SpectraLED 355 (wavelength: 355 nm).
Data analysis (exponential fit) was done using the software suite DataStation and DAS6 analysis software. The fit is specified using the chi-squared-test.

Photoluminescence Quantum Yield Measurements

[0384] For photoluminescence quantum yield (PLQY) measurements an Absolute PL Quantum Yield Measurement C9920-03G system (Hamamatsu Photonics) is used. Quantum yields and CIE coordinates were determined using the software U6039-05 version 3.6.0. Emission maxima are given in nm, quantum yields 4) in % and CIE coordinates as x,y values.

[0385] PLQY was determined using the following protocol: [0386] 1) Quality assurance: Anthracene in ethanol (known concentration) is used as reference [0387] 2) Excitation wavelength: the absorption maximum of the organic molecule is determined and the molecule is excited using this wavelength [0388] 3) Measurement [0389] Quantum yields are measured for sample of solutions or films under nitrogen atmosphere. The yield is calculated using the equation:

[00001] $Φ_{PL} = \frac{n_{photon}, emited}{n_{photon}, absorbed} = \frac{\int \frac{λ}{h c} [{Int}_{emitted}^{sample} (λ) - {Int}_{absorbed}^{sample} (λ)] d λ}{\int \frac{λ}{h c} [{Int}_{emitted}^{reference} (λ) - {Int}_{absorbed}^{reference} (λ)] d λ}$ [0390] wherein n.sub.photon denotes the photon count and Int. is the intensity.

Production and Characterization of Organic Electroluminescence Devices

[0391] Via vacuum-deposition methods OLED devices comprising organic molecules according to the invention can be produced. If a layer contains more than one compound, the weight-percentage of one or more compounds is given in %. The total weight-percentage values amount to 100%, thus if a value is not given, the fraction of this compound equals to the difference between the given values and 100%.

[0392] The not fully optimized OLEDs are characterized using standard methods and measuring electroluminescence spectra, the external quantum efficiency (in %) in dependency on the intensity, calculated using the light detected by the photodiode, and the current. The OLED device lifetime is extracted from the change of the luminance during operation at constant current density. The LT50 value corresponds to the time, where the measured luminance decreased to 50% of the initial luminance, analogously LT80 corresponds to the time point, at which the measured luminance decreased to 80% of the initial luminance, LT97 to the time point, at which the measured luminance decreased to 97% of the initial luminance etc.

[0393] Accelerated lifetime measurements are performed (e.g. applying increased current densities). Exemplarily LT80 values at 500 cd/m.sup.2 are determined using the following equation:

[00002] $LT 80 (500 \frac{{cd}^{2}}{m^{2}}) = LT 80 (L_{0}) {(\frac{L_{0}}{5 0 0 \frac{{cd}^{2}}{m^{2}}})}^{1.6}$

wherein L.sub.0 denotes the initial luminance at the applied current density.

[0394] The values correspond to the average of several pixels (typically two to eight), the standard deviation between these pixels is given. Figures show the data series for one OLED pixel.

Example D1 and Comparative Examples C1

[0395] ##STR00218## ##STR00219##

TABLE-US-00001 TABLE 1 Properties of the materials. Example compound S1 [eV] T1 [eV] λ.sub.max.sup.PMMA [nm] TTA material H.sup.N TTA1 3.16 TADF material E.sup.B TADF1 2.87 2.80 476 NRCT emitter S.sup.B NRCT1 2.65 2.47 495

TABLE-US-00002 TABLE 2 Setup of an example organic electroluminescent device (OLED), wherein different ingredients were co-deposited in layer 5 (all percentages refer to weight percent) Layer Thickness D1 C1 9 100 nm Al Al 8 2 nm Liq Liq 7 11 nm NBPhen NBPhen 6 20 nm ET1 ET1 5 20 nm TTA1 (92%): TTA1 (99%): TADF1 (7%): NRCT1 (1%) NRCT1 (1%) 4 10 nm HT2 HT2 3 50 nm HT1 HT1 2 7 nm HAT-CN HAT-CN 1 50 nm ITO ITO substrate glass glass

[0396] Device D1 yielded an external quantum efficiency (EQE) at 1000 cd/m.sup.2 of 7.03±0.05% and an LT95 value at 15 mA/cm.sup.2 of 11.2 h. The emission maximum is at 488 nm with a FWHM of 28 nm at 3.4 V.

[0397] Comparative device C1 comprise the same layer arrangement as device D1, except that the emitting layer of C1 contains only TTA1 and NRCT1.

[0398] Device C1 yielded an external quantum efficiency (EQE) at 1000 cd/m.sup.2 of 9.18±0.08% and an LT95 value at 15 mA/cm.sup.2 of 0.9 h. The emission maximum is at 488 nm with a FWHM of 28 nm at 3.4 V.

[0399] In comparison to device C1, device D1 shows an EQE at 1000 cd/m.sup.2, which is reduced by a factor of 1.31, while the LT95 value at 15 mA/cm.sup.2 is increased by a factor of 12.4, while for both devices, i.e. C1 and D1, the emission maximum and FWHM, measured at 3.4 V, remain unchanged.

Examples D2 and Comparative Example C2

[0400] ##STR00220##

TABLE-US-00003 TABLE 3 Properties of the materials. Example compound S1 [eV] T1 [eV] λ.sub.max.sup.PMMA [nm] TTA material H.sup.N TTA1 3.16 TADF material E.sup.B TADF2 2.90 2.86 468 NRCT emitter S.sup.B NRCT2 2.62 2.83 458

[0401] For TADF2, the S1, T1 and I.sub.max.sup.PMMA values were measured at a concentration of 10% in PMMA.

TABLE-US-00004 TABLE 4 Setup of an example organic electroluminescent device (OLED) (the percentages refer to weight percent) Layer Thickness D2 C2 9 100 nm Al Al 8 2 nm Liq Liq 7 11 nm NBPhen NBPhen 6 20 nm ET1 ET1 5 20 nm TTA1 (92%): TTA1 (99%): TADF2 (7%): NRCT2 (1%) NRCT2 (1%) 4 10 nm HT2 HT2 3 50 nm HT1 HT1 2 7 nm HAT-CN HAT-CN 1 50 nm ITO ITO substrate glass glass

[0402] Device D2 yielded an external quantum efficiency (EQE) at 1000 cd/m.sup.2 of 7.64±0.03% and an LT95 value at 15 mA/cm.sup.2 of 16.2 h. The emission maximum is at 460 nm with a FWHM of 26 nm at 4.1 V.

[0403] Comparative device C2 comprise the same layer arrangement as device D2, except that the emitting layer of C2 contains only TTA1 and NRCT2.

[0404] Device C2 yielded an external quantum efficiency (EQE) at 1000 cd/m.sup.2 of 9.81±0.02% and an LT95 value at 15 mA/cm.sup.2 of 2.6 h. The emission maximum is at 460 nm with a FWHM of 26 nm at 4.2 V.

[0405] In comparison to device C2, device D2 shows an EQE at 1000 cd/m.sup.2, which is reduced by a factor of 1.28, while the LT95 value at 15 mA/cm.sup.2 is increased by a factor of 6.2, while for both devices, i.e. C2 and D2, the emission maximum and FWHM, measured at 4.1 V and 4.2 V, respectively, remain unchanged.

ORGANIC ELECTROLUMINESCENT DEVICE

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Cpc classification

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H10K85/6572

ELECTRICITY

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H10K85/654

ELECTRICITY

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H10K50/11

ELECTRICITY

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C09K11/06

CHEMISTRY; METALLURGY

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H10K85/626

ELECTRICITY

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C09K2211/1018

CHEMISTRY; METALLURGY

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H10K2101/10

ELECTRICITY

International classification

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C09K11/06

CHEMISTRY; METALLURGY

Abstract

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