Funder: EC | EC Seventh Framework Programm | FP7 Ideas: European Research Council (FP7-IDEAS-ERC - Specific Programme: "Ideas" Implementing the Seventh Framework Programme of the European Community for Research, Technological Development and Demonstration Activities (2007 to 2013)); doi: https://doi.org/10.13039/100011199; Grant(s): 338944-GOCATFunder: Samsung Display Corp. (SDC)Carbene-metal-amide type photoemitters based on CF$_3$-substituted
carbazolate ligands show sky-blue to deep-blue photoluminescence from
charge-transfer excited states. They are suitable for incorporation into
organic light-emitting diodes (OLEDs) by thermal vapour deposition techniques,
either embedded within a high-triplet-energy host, or used host-free. We report
high-efficiency OLEDs with emission ranging from yellow to blue (Commission
Internationale de l'\'Eclairage (CIE) coordinates from [0.35, 0.53] to [0.17,
0.17]). The latter show a peak electroluminescence external quantum efficiency
(EQE) of 20.9 $\%$ in a polar host. We observe that the relative energies of CT
and $^{3}$LE states influence the performance of deep-blue emission from
carbene-metal-amide materials. We report prototype host-free blue devices with
peak external quantum efficiency of 17.3 $\%$, which maintain high performance
at brightness levels of 100 cd m$^{-2}$

Bochmann, Manfred

Chotard, Florian

Conaghan, Patrick J

Credgington, Dan

Greenham, Neil C

Jones, Saul TE

Matthews, Campbell SB

Romanov, Alexander S

arXiv

Carbene-metal-amides are soluble and thermally stable materials which have recently emerged as emitters in high-performance organic light-emitting diodes. Here we synthesise carbene-metal-amide photoemitters with CF3-substituted ligands to show sky-blue to deep-blue photoluminescence from charge-transfer excited states. We demonstrate that the emission colour can be adjusted from blue to yellow and observe that the relative energies of charge transfer and locally excited triplet states influence the performance of the deep-blue emission. High thermal stability and insensitivity to aggregation-induced luminescence quenching allow us to fabricate organic light-emitting diodes in both host-free and host-guest architectures. We report blue devices with a peak external quantum efficiency of 17.3% in a host-free emitting layer and 20.9% in a polar host. Our findings inform the molecular design of the next generation of stable blue carbene-metal-amide emitters

Conaghan, Patrick J.

Matthews, Campbell S. B.

Jones, Saul T. E.

Greenham, Neil C.

Romanov, Alexander S.

The University of Manchester - Institutional Repository

Highly efficient blue organic light-emitting diodes based on carbene-metal-amides

Apollo (Cambridge)

Highly efficient blue organic light-emitting diodes based on carbene-metal-amides.

Zip folder contains a series of sub folders each containing a certain type of experimental data. The experiential data is then split by compound (compounds 1, 2 ,3 and 4). “Device data” contains JVL (voltage, current density, brightness and EQE) and electroluminescence spectra in csv files, with labelled headers. Device data files are labelled by compound number and host material of emissive layer (no labelled host material implies a pure emissive layer of compound #). Electrochemistry contains xls files of oxidation and reduction potential data with labelled headers. Also included are files collating the data into plots (jpg and opj files). HRMassspec contains pdf files with the mass spectra of as labelled complexes. All peaks are labelled with relative intensity. NMR contains data relating to the synthesis of complexes and intermediate molecules. Standard NMR data analysis software is required to interpret the data. Software examples include “topspin” and “mestrenova”. “Photoluminescence” contains opju files with data for the photoluminescence of complexes and labelled plots. “TGA” contains txt and xlsx files of TGA data and is also collated into plots in jpg and opju files. UV-vis contains xls files of absorption spectra with labelled headers. Data is also collated into plots in jpg and opju format

Conaghan, Patrick

Matthews, Campbell

Jones, Saul

Greenham, Neil

Romanov, Alexander

Research data supporting "Highly Efficient Blue Organic Light-Emitting Diodes Based on Carbene-Metal-Amides"

1       Supplementary Information for  Highly Efficient Blue Organic Light-Emitting Diodes Based on Carbene-Metal-Amides  Conaghan et al.                2  Supplementary Figures     Supplementary Figure 1. TGA curves for gold complexes 1 and 2. Thermal gravimetric analysis (TGA) for complexes 1 and 2 with a decomposition temperature (Td).   Supplementary Figure 2. Intermolecular interactions for complex 2.  The scheme for the intermolecular C–H···π interaction for complex 2. Ellipsoids are shown at 50 % probability. 3        Supplementary Figure 3. Cyclic voltammetry for complexes 1 and 2. (a) reduction (blue) and oxidation (red) cyclic voltammetry scans for gold complex 1. (b) Full range cyclic voltammogram for gold complex 2. Recorded using a glassy carbon electrode in MeCN solution (1.4 mM) with [n-Bu4N]PF6 as supporting electrolyte (0.13 M), scan rate 0.1 Vs–1.  b) a) 4   Supplementary Figure 4. Photoluminescence spectra for complex 1–4. Emission spectra for complexes  CMA1 (a), CMA4 (b), 1 (c) and 2 (d) in MeTHF solutions at 77 and 298K (excitation at 360 nm, under nitrogen).    5   Supplementary Figure 5. Photoluminescence spectra for complex 1–4. PL spectra of (a) 3 and (b) 4 at 298K as crystals, in neat film, in frozen MeTHF solution and in liquid toluene solution (excitation at 365 nm).     Supplementary Figure 6. Electroluminescence spectra.  Normalised electroluminescence spectra for devices incorporating 2, 3 and 4 in host-free and host-guest structures.  6   Supplementary Figure 7. Current density-voltage-luminance (J-V-L) curves. a Current density-voltage. b luminance-voltage characteristics for OLEDs based on complexes 3 and 4    Supplementary Figure 8. External electroluminescence quantum efficiency. External Quantum efficiency as a function of current density for OLEDs based on 3 and 4. 7   Supplementary Figure 9. OLED device lifetime curves.  OLED device operating lifetime curves (initial luminance 100 cd/m2) at constant current under vacuum for complexes 1 (a), 3 (b) and 4 (c).      Supplementary Figure 10. Synthesis of compound A. Synthetic scheme to obtain N-(3'-(tert-butyl)-5-(trifluoromethyl)-[1,1'-biphenyl]-2-yl)acetamide (A).           8   a  b  9   c  Supplementary Figure 11. NMR spectra for N-(3'-(tert-butyl)-5-(trifluoromethyl)-[1,1'-biphenyl]-2-yl)acetamide. (a) 1H NMR (300 MHz, CDCl3); (b) 13C NMR (75 MHz, CDCl3); (c) 19F NMR (282 MHz, CDCl3).    Supplementary Figure 12. Synthesis of compound B. Synthetic scheme to obtain 6-(tert-butyl)-3-(trifluoromethyl)-9-acetylcarbazole (B).    10   a                11  b  c  Supplementary Figure 13. NMR spectra for 6-(tert-butyl)-3-(trifluoromethyl)-9-acetylcarbazole. (a) 1H NMR (300 MHz, CDCl3); (b) 13C NMR (75 MHz, CDCl3); (c) 19F NMR (282 MHz, CDCl3). 12     Supplementary Figure 14. Synthesis of compound C. Synthetic scheme to obtain 6-(tert-butyl)-3-(trifluoromethyl)-9H-carbazole (C).         a  13  b  c  Supplementary Figure 15. NMR spectra for 6-(tert-butyl)-3-(trifluoromethyl)-9-acetylcarbazole. (a) 1H NMR (300 MHz, CDCl3); (b) 13C NMR (75 MHz, CDCl3); (c) 19F NMR (282 MHz, CDCl3). 14  a  b  15  c  Supplementary Figure 16. NMR spectra for complex 1. (a) 1H NMR (300 MHz, CDCl3); (b) 13C NMR (75 MHz, CDCl3); (c) 19F NMR (282 MHz, CDCl3).               16  a  b  17  c  Supplementary Figure 17. NMR spectra for complex 2. (a) 1H NMR (300 MHz, CDCl3); (b) 13C NMR (75 MHz, CDCl3); (c) 19F NMR (282 MHz, CDCl3).  Supplementary Methods Synthesis of N-(3'-(tert-butyl)-5-(trifluoromethyl)-[1,1'-biphenyl]-2-yl)acetamide: N-(2-chloro-4-(trifluoromethyl)phenyl)acetamide (1 eq., 5.05 mmol, 1.20 g), 3-(tert-butyl)phenylboronic acid (2.0 eq., 10.1 mmol, 1.80 g,) and potassium phosphate trihydrate (2.0 eq., 10.1 mmol, 2.33 g) were mixed in THF/H2O 20:1 (10 mL) and purged with argon. SPhos Pd G2 (1 mol%, 0.051 mmol, 37 mg) was added and the mixture was heated at 80°C for 16 h. Reaction was cooled to r.t., Et2O (30 mL) was added and the mixture was filtered through Celite®. The filtrate was diluted with AcOEt (100 mL), washed with water and brine, and dried with MgSO4. The solvent was evaporated and the residue was purified by silica column chromatography (PE/AcOEt) to afford the product as an off-white solid (92%, 1.55 g). 1H NMR (300 MHz, CDCl3): δ 8.53 (d, J = 8.7 Hz, 1H), 7.61 (pseudo dd, J = 8.7, 2.2 Hz, 1H), 7.52 – 7.42 (m, 3 x 1H overlapped), 7.40 – 7.37 (m, 1H), 7.37 – 7.32 (bs, NH), 7.19 (pseudo dt, J = 6.6, 1.9 Hz, 1H), 2.05 (s, 3H, Ac), 1.37 (s, 9H, tBu). 13C NMR (75 MHz, CDCl3) δ 168.4 (s, 18  C=O), 152.7 (s, C–tBu), 138.0 (s, Cq), 136.4 (s, Cq), 132.2 (s, Cq)), 129.5 (s, CH), 127.1 (q, J = 3.6 Hz, CH–C–CF3), 126.4 (s, CH), 126.3 (s, CH), 125.8 (s, CH), 125.5 (q, J = 3.7 Hz, CH–C–CF3), 124.2 (q, J = 271.8 Hz, CF3), 120.8 (s, CH), 35.1 (s, C(CH3)3), 31.5 (s, C(CH3)3), 25.0 (s, CH3 Ac), (Cipso–CF3 was not observed due to overlap with aromatic signals). 19F NMR (282 MHz, CDCl3) δ -62.1 ppm. Anal. Calcd. for C19H20F3NO 335.37): C, 68.05; H, 6.01; N, 4.18. Found: C, 68.17; H, 6.18; N, 4.31. See Supplementary Figs. 10 and 11.  Synthesis of 6-(tert-butyl)-3-(trifluoromethyl)-9-acetylcarbazole: In an oven-dried Schlenk tube, under argon, N-(3'-(tert-butyl)-5-(trifluoromethyl)-[1,1'-biphenyl]-2-yl)acetamide (1 eq., 4.47 mmol, 1.50 g), Cu(OAc)2 (20 mol%, 0.89 mmol, 162 mg), Pd(OAc)2 (2 mol%, 0.089 mmol, 20 mg) and 3 Å molecular sieves were mixed in toluene (20 mL). The flask was purged by oxygen and heated at 120°C. The Pd(OAc)2 was added every 8 h (4 × 20 mg). The reaction was monitored by 19F NMR indicating full completion after 48 h. The mixture was cooled to r.t., diluted with AcOEt (60 mL) and filtered through Celite®. The filtrate was diluted with AcOEt (100 mL) washed with water and brine and dried with MgSO4. The solvent was evaporated and the residue was purified by silica column chromatography (PE/AcOEt) to afford the product as an off-white solid (68%, 1.01 g). 1H NMR (300 MHz, CDCl3): δ 8.46 (d, J = 8.8 Hz, 1H, CH1), 8.27 (pseudo s, 1H, CH4), 8.04 (d, J = 2.1 Hz, 1H, CH5), 8.01 (d, J = 8.9 Hz, 1H, CH8), 7.71 (pseudo dd, J = 8.8, 1.9 Hz, 1H, CH2), 7.60 (dd, J = 8.9, 2.1 Hz, 1H, CH7), 2.90 (s, 3H, Ac), 1.45 (s, 9H, tBu). 13C NMR (75 MHz, CDCl3) δ 170.1 (s, C=O), 147.5 (C–tBu), 140.9 (s, Cq), 137.1 (s, Cq), 126.8 (s, Cq), 126.1 (s, CH7), 126.0 (q, J = 32.6 Hz, C–CF3), 125.6 (s, Cq), 124.7 (q, J = 271.7 Hz, CF3), 124.2 (q, J = 3.6 Hz, CH2), 117.0 (s, CH1 overlapped with CH4), 116.9 (q, J = 3.9 Hz, CH4 overlapped with CH1), 116.8 (s, CH5), 115.6 (s, CH8), 34.9 (s, C(CH3)3, 31.8 (C(CH3)3, 27.8 (s, CH3 Ac). 19F NMR (282 MHz, CDCl3) δ -61.2. Anal. Calcd. for C19H18F3NO (333.35): C, 68.46; H, 5.44; N, 4.20. Found: C, 68.13; H, 5.68; N, 3.97. See Supplementary Figs. 12 and 13.  Synthesis of 6-(tert-butyl)-3-(trifluoromethyl)-9H-carbazole. DBU (2 eq., 6.06 mmol, 904 µL) was added to 6-(tert-butyl)-3-(trifluoromethyl)-9-acetylcarbazole (1 eq., 3.03 mmol, 1.01 g) in MeOH (30 mL), and the mixture was refluxed for 6 h. The reaction was cooled to r.t. and volatiles were evaporated. AcOEt (120 mL) was added, washed with water and brine, and dried 19  over MgSO4. The residue was purified by silica column chromatography (PE/AcOEt) to afford the product as a white solid (91%, 800 mg). 1H NMR (300 MHz, CDCl3): δ 8.37 (s, 1H, CH4), 8.16 (bs, 1H, NH), 8.12 (pseudo s, 1H, CH5), 7.64 (pseudo dd, J = 8.5, 1.7 Hz, 1H, CH2), 7.56 (dd, J = 8.6, 1.9 Hz, 1H, CH8), 7.47 (d, J = 8.5 Hz, 1H, CH1), 7.41 (d, J = 8.6 Hz, 1H, CH7), 1.45 (s, 9H, tBu). 13C NMR (75 MHz, CDCl3) δ 143.6 (s, C–tBu), 141.5 (s, Cq), 138.2 (s, Cq), 125.5 (q, J = 271.2 Hz, CF3), 125.0 (s, CH7), 123.4 (s, Cq), 122.8 (s, Cq), 122.5 (q, J = 3.7 Hz, CH2), 121.7 (q, J = 32.1 Hz, C–CF3), 117.9 (q, J = 4.1 Hz, CH4), 116.8 (s, CH5), 110.7 (s, CH1), 110.6 (s, CH8), 34.9 (s, C(CH3)3), 32.1 (s, C(CH3)3). 19F NMR (282 MHz, CDCl3) δ -60.1. Anal. Calcd. for C17H16F3N (291.32): C, 70.09; H, 5.54; N, 4.81. Found: C, 69.82; H, 5.72; N, 4.63. See Supplementary Figs. 14 and 15.  X-Ray Crystallography.  Crystals of 1 and 2 suitable for X-ray diffraction study were obtained by layering a toluene solution with hexanes. Complex 1 and 2 crystallizes with two independent molecules in the unit cell and molecules of toluene. The CF3-group was disordered over two half-populated positions for the complex 1 (independent molecule A). For the final refinement, the contribution of severely disordered toluene molecules in the crystals of 1 was removed from the diffraction data with PLATON/SQUEEZE.1,2 Crystals were mounted in oil on glass fiber and fixed on the diffractometer in a cold nitrogen stream. Data were collected using an Oxford Diffraction Xcalibur-3/Sapphire3-CCD diffractometer with graphite monochromated Mo Kα radiation (λ = 0.71073 Å) at 140 K. Data were processed using the CrystAlisPro-CCD and –RED software.3 The structure was solved by direct methods and refined by the full-matrix least-squares against F2 in an anisotropic (for non-hydrogen atoms) approximation. All hydrogen atom positions were refined in isotropic approximation in a “riding” model with the Uiso(H) parameters equal to 1.2 Ueq(Ci), for methyl groups equal to 1.5 Ueq(Cii), where U(Ci) and U(Cii) are respectively the equivalent thermal parameters of the carbon atoms to which the corresponding H atoms are bonded. All calculations were performed using the SHELXTL software.4  The principal crystallographic data and refinement parameters: Complex 1, CCDC number 1916996, C51H62AuF3N2, Monoclinic, space group P21/n, a = 23.0603(9) Å, b = 15.7169(5) Å, c = 26.0909(9) Å,  = 103.114(4)°, V = 9209.7(6) Å3, Z = 8, dcalc = 1.380 g cm−3,  = 3.242 mm−1, colorless/block, crystal size 0.25 × 0.21 × 0.09 mm, F(000) 20  = 3904, Tmin/Tmax 0.73420/1.00000, R1 = 0.0341 (from 18085 unique reflections with I>2σ(I); Rint = 0.0449, Rsigma = 0.0392) and wR2 = 0.0852 (from all 73935 unique reflections), GOF = 1.096, Δρmin/Δρmax = 1.65/–1.28.  Complex 2, CCDC number 1916995, C41H45AuF6N2, Triclinic, space group P-1, a = 13.2995(6) Å, b = 14.8662(6) Å, c = 26.4244(10) Å, α = 74.133(4)°,  = 77.531(3)°, γ = 71.883(4)°,  V = 4727.0(4) Å3, Z = 4, dcalc = 1.232 g cm−3,  = 3.160 mm−1, colorless/block, crystal size 0.16 × 0.11 × 0.07 mm, F(000) = 1752, Tmin/Tmax 0.70618/1.00000, R1 = 0.0396 (from 18562 unique reflections with I>2σ(I); Rint = 0.0548, Rsigma = 0.0852) and wR2 = 0.0754 (from all 41002 unique reflections), GOF = 1.022, Δρmin/Δρmax = 1.15/–1.28.    Supplementary References  1. Spek, A. L. Structure validation in chemical crystallography. Acta Cryst. D65, 148–155 (2009). 2. van der Sluis, P. & Spek, A. L. BYPASS: an effective method for the refinement of crystal structures containing disordered solvent regions. Acta Cryst. A46, 194–201 (1990). 3. Programs CrysAlisPro, Oxford Diffraction Ltd., Abingdon, UK (2010). 4. Sheldrick, G.M. SHELX-97 and SHELX-2018/3 – Programs for crystal structure determination (SHELXS) and refinement (SHELXL), Acta Cryst. C71, 3–8 (2015). 

Highly Efficient Blue Host-Free and Host-Guest Organic Light-Emitting
  Diodes Based on Carbene-Metal-Amides

University of East Anglia digital repository

English

Funder: EC | EC Seventh Framework Programm | FP7 Ideas: European Research Council (FP7-IDEAS-ERC - Specific Programme: "Ideas" Implementing the Seventh Framework Programme of the European Community for Research, Technological Development and Demonstration Activities (2007 to 2013)); Grant(s): 338944-GOCATCarbene-metal-amides are soluble and thermally stable materials which have recently emerged as emitters in high-performance organic light-emitting diodes. Here we synthesise carbene-metal-amide photoemitters with CF3-substituted ligands to show sky-blue to deep-blue photoluminescence from charge-transfer excited states. We demonstrate that the emission colour can be adjusted from blue to yellow and observe that the relative energies of charge transfer and locally excited triplet states influence the performance of the deep-blue emission. High thermal stability and insensitivity to aggregation-induced luminescence quenching allow us to fabricate organic light-emitting diodes in both host-free and host-guest architectures. We report blue devices with a peak external quantum efficiency of 17.3% in a host-free emitting layer and 20.9% in a polar host. Our findings inform the molecular design of the next generation of stable blue carbene-metal-amide emitters

Matthews, Campbell S B

Jones, Saul T E

https://www.repository.cam.ac.uk/bitstream/1810/319656/2/41467_2020_15369_MOESM1_ESM.pdf

Highly Efficient Blue Host-Free and Host-Guest Organic Light-Emitting Diodes Based on Carbene-Metal-Amides

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Apollo (Cambridge)

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Apollo (Cambridge)

University of East Anglia digital repository

Apollo (Cambridge)