Supporting Information High-Efficiency Organic Light-Emitting Diodes Based on Sublimable Cationic Iridium(III) Complexes with Sterically Hindered Spacers Dongxin Ma 1 *, Ruihuan Liu 1, Chen Zhang 1, Yong Qiu 1, Lian Duan 1,2 * 1 Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China. 2 Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China. E-mail: madongxin1130@qq.com; duanl@mail.tsinghua.edu.cn Supplemental Experimental Section Pages S1-S61 Figures S1-S52 Tables S1-S3 S1
Supplemental Experimental Section Structural Characterization Methods. The ESI mass spectrometry was performed with Thermo Electron Corporation Finnigan LTQ. 1 H NMR and 19 F NMR spectra were recorded on a JOEL JNM-ECA600 NMR spectrometer. X-Ray Crystallography. The single crystal X-ray diffraction data collections were carried out on a Rigaku AFC-10/Saturn 724+ charge-coupled device (CCD) diffractometer equipped with graphite-monochromatized Mo Kα radiation (λ = 0.71073 Å) using the multi-scan technique. The structures were determined by direct methods using SHELXS-97 and refined by full-matrix least-squares procedures on F2 with SHELXL-2008. All the non-hydrogen atoms were obtained from the difference Fourier map and subjected to anisotropic refinement by full-matrix least squares on F2. The hydrogen atoms were obtained geometrically and treated as riding on the parent atoms or constrained in the locations during refinements. Photophysical, Electrochemical and Thermal Measurements. Absorption spectra was measured by an ultraviolet-visible spectrophotometer (Agilent 8453), while PL spectra were characterized by a fluorospectrophotometer (HITACHI, F-7000). PLQYs in solutions and neat films were measured at the excitation wavelength of 400 nm (Hamamutsu Photonics K. K., C9920-03). The excited state lifetimes were measured by a lifetime and steady state spectrometer (Edinburgh Instruments, FLS 980) with time-correlated single-photon counting (TCSPC) technique at the corresponding emission wavelength. CV was probed in oxygen-free anhydrous solutions on a Princeton Applied Research potentiostat/ galvanostat Model 283 voltammetric analyzer at a scanning rate of 100 mv/s with a platinum plate as the working S2
electrode, a silver wire as the pseudo-reference electrode and a platinum wire as the counter electrode. The oxidation potentials were measured in N,N-dimethylformamide solutions with 40 mg/ml tetrabutylammonium perchlorate supporting electrolyte, while the reduction potentials were measured in acetonitrile solutions with 35 mg/ml tetrabutylammonium hexafluorophosphate supporting electrolyte. Ferrocene served as the internal standard. TGA was measured by a thermogravimetric analyzer (TA Instruments Q5000) with a heating rate of 10 o C/min under nitrogen-flow conditions. Quantum Chemical Calculations. Calculations on the volume of both the coordinated iridium(iii) cations and tetraphenylborate-type anions were performed by means of DFT using opt volume=tight rb3lyp/gen geom=connectivity pseudo=read. Calculations on the ground electronic states of the emissive coordinated iridium(iii) cations were performed by means of DFT using opt=tight rb3lyp/gen geom=connectivity pseudo=read. Calculations on the excited electronic states of the emissive coordinated iridium(iii) cations were performed by means of TD-DFT using td=(50-50,nstates=5) b3lyp/gen geom=connectivity pseudo=read. The doubleξ quality basis sets were 6-31G* for the carbon, hydrogen, nitrogen, fluorine and LANL2DZ for iridium. The inner core electrons of iridium(iii) were replaced by an effective core potential (ECP), with outer core of 5s 2 5p 6 electrons and the 5d 6 valence electrons. All the quantum chemical calculations were performed with Gaussian 09 software package using a spinrestricted formalism (see the reference). Device Fabrication and Evaluation. The OLEDs were grown on the cleaned, ultravioletozone-treated and ITO-coated glass substrates, with a sheet resistance of about 20 Ω per sq. S3
Each functional material layer was successively fabricated thereon by vacuum evaporation deposition under a low pressure below 5 10-4 Pa. Current density-voltage and luminancevoltage curves were collected with Keithley 4200 semiconductor system, while the EL spectra were recorded by a Photo Research PR705 spectrophotometer. All the device measurements were carried out at room temperature in the ambient air without further encapsulations. Reference Frisch, M. J.; Trucks, G. W.; Schelegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery, J. A.; Jr., Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers, E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.; Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox, J. E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.; Morokuma, K.; Zakrzewski, V. G.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, O.; Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian 09, Revision B.01; Gaussian, Inc., Wallingford CT, 2010. S4
Figure S1. The synthetic routes of complexes 1-4. S5
Figure S2. The synthetic routes of complexes 5-10. S6
Figure S3. The single-crystal structure of [Ir(ppy)2(bpy)][BF4] (complex 1). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. Figure S4. The single-crystal structure of [Ir(ppy)2(bpy)][PF6] (complex 2). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. S7
Figure S5. The single-crystal structure of [Ir(ppy)2(bpy)][B(5FPh)4] (complex 3). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. Figure S6. The single-crystal structure of [Ir(ppy)2(bpy)][B(dCF3Ph)4] (complex 4). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. S8
Figure S7. The single-crystal structure of [Ir(ppy)2(dtb-bpy)][B(5FPh)4] (complex 5). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. Figure S8. The single-crystal structure of [Ir(ppy)2(dtb-bpy)][B(dCF3Ph)4] (complex 6). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. S9
Figure S9. The single-crystal structure of [Ir(phq)2(dtb-bpy)][B(5FPh)4] (complex 7). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. Figure S10. The single-crystal structure of [Ir(phq)2(dtb-bpy)][B(dCF3Ph)4] (complex 8). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. S10
Figure S11. The single-crystal structure of [Ir(piq)2(dtb-bpy)][B(5FPh)4] (complex 9). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. Figure S12. The single-crystal structure of [Ir(piq)2(dtb-bpy)][B(dCF3Ph)4] (complex 10). Here the thermal ellipsoids are drawn at the 30% probability level. The solvent molecules and hydrogen atoms are omitted for clarity. The unlabeled atoms are carbon atoms. S11
Figure S13. The packing view of [Ir(ppy)2(bpy)][BF4] (complex 1) along a direction. The shortest Ir-B and Ir-Ir distance is 6.168 and 7.766 Å, respectively. S12
Figure S14. The packing view of [Ir(ppy)2(bpy)][PF6] (complex 2) along a direction. The shortest Ir-P and Ir-Ir distance is 6.112 and 7.924 Å, respectively. S13
Figure S15. The packing view of [Ir(ppy)2(bpy)][B(5FPh)4] (complex 3) along a direction. The shortest Ir-B and Ir-Ir distance is 8.487 and 9.061 Å, respectively. S14
Figure S16. The packing view of [Ir(ppy)2(bpy)][B(dCF3Ph)4] (complex 4) along a direction. The shortest Ir-B and Ir-Ir distance is 9.520 and 12.536 Å, respectively. S15
Figure S17. The packing view of [Ir(ppy)2(dtb-bpy)][B(5FPh)4] (complex 5) along a direction. The shortest Ir-B and Ir-Ir distance is 8.818 and 7.356 Å, respectively. S16
Figure S18. The packing view of [Ir(ppy)2(dtb-bpy)][B(dCF3Ph)4] (complex 6) along a direction. The shortest Ir-B and Ir-Ir distance is 8.499 and 11.566 Å, respectively. S17
Figure S19. The packing view of [Ir(phq)2(dtb-bpy)][B(5FPh)4] (complex 7) along a direction. The shortest Ir-B and Ir-Ir distance is 9.224 and 8.789 Å, respectively. S18
Figure S20. The packing view of [Ir(phq)2(dtb-bpy)][B(dCF3Ph)4] (complex 8) along a direction. The shortest Ir-B and Ir-Ir distance is 8.869 and 9.476 Å, respectively. S19
Figure S21. The packing view of [Ir(piq)2(dtb-bpy)][B(5FPh)4] (complex 9) along a direction. The shortest Ir-B and Ir-Ir distance is 11.269 and 17.333 Å, respectively. S20
Figure S22. The packing view of [Ir(piq)2(dtb-bpy)][B(dCF3Ph)4] (complex 10) along a direction. The shortest Ir-B and Ir-Ir distance is 9.278 and 8.036 Å, respectively. S21
Figure S23. Absorption spectra of complexes 1-10 in anhydrous acetonitrile solutions. S22
Figure S24. PL spectra of complexes 1-10 in acetonitrile glass at 77 K. S23
Figure S25. Excited state lifetimes of complex 1 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S24
Figure S26. Excited state lifetimes of complex 2 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S25
Figure S27. Excited state lifetimes of complex 3 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S26
Figure S28. Excited state lifetimes of complex 4 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S27
Figure S29. Excited state lifetimes of complex 5 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S28
Figure S30. Excited state lifetimes of complex 6 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S29
Figure S31. Excited state lifetimes of complex 7 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S30
Figure S32. Excited state lifetimes of complex 8 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S31
Figure S33. Excited state lifetimes of complex 9 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S32
Figure S34. Excited state lifetimes of complex 10 (a) in neat films at room temperature and (b) in acetonitrile glass at 77 K. S33
Figure S35. CV of complexes 1-4 with [Ir(ppy)2(bpy)] + in oxygen-free anhydrous solutions. Ferrocence serves as the internal standard. Figure S36. CV of complexes 5 and 6 with [Ir(ppy)2(dtb-bpy)] + in oxygen-free anhydrous solutions. Ferrocence serves as the internal standard. S34
Figure S37. CV of complexes 7 and 8 with [Ir(phq)2(dtb-bpy)] + in oxygen-free anhydrous solutions. Ferrocence serves as the internal standard. Figure S38. CV of complexes 9 and 10 with [Ir(piq)2(dtb-bpy)] + in oxygen-free anhydrous solutions. Ferrocence serves as the internal standard. S35
Figure S39. TGA of complexes 1-10 under nitrogen-flow conditions. S36
Figure S40. The frontier MO surfaces of [Ir(ppy)2(bpy)] +, corresponding to an isocontour value of Ψ = 0.02 at the optimized geometry. The contribution of each mono-electronic excitation to T1 S0 and T2 S0 transitions is obtained by means of TD-DFT. All the hydrogen atoms are omitted for clarity. S37
Figure S41. The frontier MO surfaces of [Ir(ppy)2(dtb-bpy)] +, corresponding to an isocontour value of Ψ = 0.02 at the optimized geometry. The contribution of each mono-electronic excitation to T1 S0 and T2 S0 transitions is obtained by means of TD-DFT. All the hydrogen atoms are omitted for clarity. S38
Figure S42. The frontier MO surfaces of [Ir(phq)2(dtb-bpy)] +, corresponding to an isocontour value of Ψ = 0.02 at the optimized geometry. The contribution of each mono-electronic excitation to T1 S0 and T2 S0 transitions is obtained by means of TD-DFT. All the hydrogen atoms are omitted for clarity. S39
Figure S43. The frontier MO surfaces of [Ir(piq)2(dtb-bpy)] +, corresponding to an isocontour value of Ψ = 0.02 at the optimized geometry. The contribution of each mono-electronic excitation to T1 S0 and T2 S0 transitions is obtained by means of TD-DFT. All the hydrogen atoms are omitted for clarity. S40
S41
Figure S44. Molecular structures of the materials used in the OLEDs. S42
Figure S45. Characteristics of the OLEDs based on complex 3 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 3 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S43
S44
Figure S46. Characteristics of the OLEDs based on complex 4 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 4 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S45
S46
Figure S47. Characteristics of the OLEDs based on complex 5 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 5 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S47
S48
Figure S48. Characteristics of the OLEDs based on complex 6 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 6 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S49
S50
Figure S49. Characteristics of the OLEDs based on complex 7 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 7 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S51
S52
Figure S50. Characteristics of the OLEDs based on complex 8 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 8 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S53
S54
Figure S51. Characteristics of the OLEDs based on complex 9 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 9 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S55
S56
Figure S52. Characteristics of the OLEDs based on complex 10 in the structure of ITO/ HATCN (5 nm)/ NPB (40 nm)/ TCTA (10 nm)/ DIC-TRZ: x% complex 10 (12 nm)/ BPBiPA (50 nm)/ LiF (1 nm)/ Al (150 nm) at varying dopant concentrations. (a) Current density-voltage, (b) luminance-voltage and (c) current efficiency-luminance curves, (d) EL spectra. S57
S58
Table S1. Triplet excited states of the four coordinated iridium(iii) cations from quantum chemical calculations by TD-DFT. Cation Triplet State E a [ev] λ b [nm] Excitation c Nature [Ir(ppy)2(bpy)] + T1 2.18 568 HOMO LUMO (100%) dπ(ir)-π(ppy) π*(bpy) T2 2.40 517 HOMO-1 LUMO (100%) dπ(ir)-π(ppy) π*(bpy) [Ir(ppy)2(dtb-bpy)] + T1 2.29 541 HOMO LUMO (100%) dπ(ir)-π(ppy) π*(dtb-bpy) T2 2.69 461 HOMO LUMO+2 (77.3%) HOMO-1 LUMO+3 (16.1%) HOMO-2 LUMO+2 (6.6%) dπ(ir)-π(ppy) π*(ppy) dπ(ir)-π(ppy) π*(ppy) dπ(ir)-π(ppy) π*(ppy) [Ir(phq)2(dtb-bpy)] + T1 2.28 544 HOMO LUMO (93.1%) HOMO LUMO+2 (6.9%) dπ(ir)-π(phq) π*(dtb-bpy) dπ(ir)-π(phq) π*(phq) T2 2.36 525 HOMO LUMO+1 (77.5%) HOMO-1 LUMO+2 (16.7%) HOMO-2 LUMO+1 (5.8%) dπ(ir)-π(phq) π*(phq) dπ(ir)-π(phq) π*(phq) dπ(ir)-π(phq) π*(phq) [Ir(piq)2(dtb-bpy)] + T1 2.21 561 HOMO LUMO (56.5%) HOMO LUMO+1 (20.5%) HOMO-1 LUMO+2 (15.4%) HOMO-2 LUMO+1 (7.6%) dπ(ir)-π(piq) π*(dtb-bpy) dπ(ir)-π(piq) π*(piq) dπ(ir)-π(piq) π*(piq) dπ(ir)-π(piq) π*(piq) T2 2.24 554 HOMO LUMO (37.9%) HOMO LUMO+1 (28.0%) HOMO-1 LUMO+1 (11.8%) HOMO-1 LUMO+2 (10.3%) HOMO LUMO+2 (6.4%) HOMO-2 LUMO+1 (5.6%) dπ(ir)-π(piq) π*( dtb-bpy) dπ(ir)-π(piq) π*(piq) dπ(ir)-π(piq) π*(piq) dπ(ir)-π(piq) π*(piq) dπ(ir)-π(piq) π*(piq) dπ(ir)-π(piq) π*(piq) a Calculated excitation energy for the triplet excited states. b Calculated emission wavelength. c The percentage in the parenthesis denotes the contribution of each mono-electronic excitation. S59
Table S2. Detailed device characteristics of the vacuum-evaporated-deposited OLEDs based on complexes 3-6. x a [%] Von b [V] Max CE c [cd/a] CE c at 10 3 cd/m 2 [cd/a] CEc at 104 cd/m2 [cd/a] max EQEd [%] max PE e 3 1.0 2.39 40.4 37.7 33.4 13.4 38.3 >27.3 10 3 548 (0.41, 0.55) 1.5 2.40 40.3 37.0 34.4 13.3 33.1 >27.3 10 3 548 (0.41, 0.55) 2.0 2.34 40.9 39.5 35.3 13.5 40.4 >27.3 10 3 548 (0.41, 0.55) 2.5 2.40 39.2 37.5 33.4 13.1 36.1 >27.3 10 3 548 (0.42, 0.54) 4 1.0 2.38 34.1 32.5 24.1 11.2 33.0 >27.3 10 3 558 (0.43, 0.54) 1.5 2.38 35.1 33.7 25.3 11.7 36.7 >27.3 10 3 558 (0.44, 0.53) 2.0 2.39 33.8 31.8 22.6 11.4 34.9 >27.3 10 3 560 (0.44, 0.53) 2.5 2.56 35.6 34.5 22.9 12.0 28.5 >27.3 10 3 560 (0.44, 0.53) 5 1.6 2.31 45.2 41.5 39.1 14.5 36.5 >27.3 10 3 558 (0.43, 0.54) 1.9 2.31 46.5 42.8 40.4 14.8 37.9 >27.3 10 3 556 (0.43, 0.55) 2.2 2.31 45.3 41.5 39.4 14.3 37.2 >27.3 10 3 556 (0.43, 0.55) 2.5 2.31 46.4 42.9 40.7 14.8 39.5 >27.3 10 3 556 (0.43, 0.54) 6 0.8 2.54 37.5 36.0 25.2 12.1 34.9 >27.3 10 3 560 (0.44, 0.54) 1.1 2.64 35.7 32.2 21.4 11.6 34.2 >27.3 10 3 558 (0.45, 0.54) 1.4 2.48 40.7 38.5 29.5 13.5 31.8 >27.3 10 3 564 (0.44, 0.53) 1.7 2.65 33.4 30.9 21.3 11.1 30.6 >27.3 10 3 564 (0.44, 0.53) a x, dopant ratio. b Von, turn-on voltage (at the luminance of 1 cd/m 2 ). c CE, current efficiency. d EQE, external quantum efficiency. e PE, [lm/w] max L f [cd/m 2 ] λel g [nm] CIE h (x, y) power efficiency. f L, luminance. g λel, EL wavelength. h CIE, Commission Internationale de I'Elairage. S60
Table S3. Detailed device characteristics of the vacuum-evaporated-deposited OLEDs based on complexes 7-10. x a [%] Von b [V] Max CE c [cd/a] CE c at 10 3 cd/m 2 [cd/a] CEc at 104 cd/m2 [cd/a] max EQEd [%] max PE e 7 1.5 2.25 39.3 36.1 20.5 13.3 38.6 >27.3 10 3 556, 586 (sh) (0.48, 0.51) 1.7 2.19 40.6 36.5 21.7 13.8 40.9 >27.3 10 3 556, 586 (sh) (0.48, 0.51) 1.9 2.26 39.2 34.4 19.1 13.3 38.8 >27.3 10 3 556, 586 (sh) (0.48, 0.51) 2.1 2.27 38.9 36.0 20.3 13.1 38.4 >27.3 10 3 556, 586 (sh) (0.48, 0.50) 8 1.2 2.29 40.5 35.9 19.7 13.0 41.0 >27.3 10 3 556, 586 (sh) (0.48, 0.51) 1.4 2.30 48.6 44.9 30.3 15.5 49.3 >27.3 10 3 556, 586 (sh) (0.48, 0.51) 1.6 2.29 48.9 44.2 28.9 15.8 49.0 >27.3 10 3 558, 586 (sh) (0.48, 0.51) 1.8 2.33 44.6 42.3 26.4 16.1 43.8 >27.3 10 3 558, 586 (sh) (0.48, 0.50) 9 1.5 2.38 15.2 14.4 7.9 9.8 12.0 >27.3 10 3 588 (sh), 626 (0.60, 0.40) 1.7 2.40 16.5 15.4 8.9 10.7 16.6 >27.3 10 3 588 (sh), 626 (0.60, 0.40) 1.9 2.37 15.4 14.5 8.1 10.0 13.5 >27.3 10 3 588 (sh), 626 (0.60, 0.40) 2.1 2.38 15.2 14.4 7.9 9.9 12.8 >27.3 10 3 588 (sh), 626 (0.60, 0.40) 10 2.2 2.49 13.0 11.8 3.5 8.0 12.5 14.1 10 3 588 (sh), 622 (0.59, 0.40) 2.4 2.42 18.0 16.0 6.1 11.1 19.1 18.8 10 3 588 (sh), 624 (0.59, 0.40) 2.6 2.46 16.7 15.5 5.4 10.3 17.1 17.3 10 3 588 (sh), 624 (0.59, 0.40) 2.8 2.52 14.5 13.3 4.4 8.9 13.2 16.7 10 3 588 (sh), 624 (0.59, 0.40) a x, dopant ratio. b Von, turn-on voltage (at the luminance of 1 cd/m 2 ). c CE, current efficiency. d EQE, external quantum efficiency. e PE, [lm/w] max L f [cd/m 2 ] λel g [nm] CIE h (x, y) power efficiency. f L, luminance. g λel, EL wavelength, sh denotes the shoulder peak. h CIE, Commission Internationale de I'Elairage. S61