Supporting Information

Transcription

1 Supporting Information Development of a Highly Efficient Hybrid White Organic-Light- Emitting Diode with a Single Emission Layer by Solution Processing Jun-Yi Wu and Show-An Chen * Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University, Hsinchu 30013, Taiwan, Republic of China * sachen@che.nthu.edu.tw. S-1

2 S1. Experimental Section S2. The performance characteristics of the devices having 26DCzPPy doped with different weight ratio TCTA. S3. The EL spectra from the device with 26DCzPPy:HTM (8:2 by weight) as the mixed host and TADF material DMAC-TRZ as a blue emission dopant. S4. The EL spectra from the device with the mixed host 26DCzPPy:TCTA (8:2 by weight) and different contents of DMAC-TRZ as a blue dopant. S5. The spectra of EL and PL with different red dopant concentration. S CIE coordinates for Blue and the White Organic Light-Emitting Diodes S1. Experimental Section Materials. The hole injection material PEDOT:PSS (Baytron PVP. AI-4083) with a conductivity of S cm -1 was purchased from Heraeus. The bipolar host 2,6-bis[3-(carbazol-9-yl)phenyl]pyridine (26DCzPPy) and the hole transport materials tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and 4,4 -Cyclohexylidenebis[N,N-bis(4- methylphenyl)benzenamine] (TAPC) were purchased from Ultra Fine Chemical Technology Corporation, Taiwan. The blue TADF material of 9,9-dimethyl-9,10- dihydroacridine-2,4,6-triphenyl-1,3,5-triazine (DMAC-TRZ) and the electron transport material TmPyPB were purchased from Shine Materials Technology Corporation, Taiwan. The red phosphor iridium(iii) bis(2-phenylquinoly-n,c 2 )-dipivaloylmethane [Ir(dpm)PQ2] and red fluorescent emitter 4-(dicyanomethylene)-2-tert-butyl-6- S-2

3 (1,1,7,7-tetramethyljulolidyl-9-enyl)-4H pyran (DCJTB) were purchased from Luminescence Technology Corporation (Lumtec), Taiwan. Device fabrication. For the device preparation, an indium tin oxide (ITO) glass substrate was exposed to oxygen plasma at a power of 50 W and a pressure of 193 mtorr for 5 min, and then a thin hole injection layer of PEDOT:PSS layer was spin-coated on the plasma-treated ITO. After drying for 30 min at 140 under vacuum to remove the residual water, 26DCzPPy blending with 20 wt % TCTA or TAPC (26DCzPPy:TCTA or TAPC=8:2 by weight) as the mixed host and DMAC-TRZ of various contents as the blue emission dopant were dissolved in chlorobenzene (CB) to make the blue TADF solutions (15 mg/ml). For the preparation of TADF white emission solutions in CB, the red phosphor Ir(dpm)PQ2 or red fluorescent emitter DCJTB were added into the blue TADF mixture and then dissolved them in CB. The white and blue emission layers (45 nm) were prepared by spin-coating on the PEDOT:PSS, and then thermally annealed at 120 in glove box (N2 environment) to remove residual solvent (CB). TmPyPB layer used as the electron transporting and hole/exciton blocking layer was deposited on top of the emission layer by thermal evaporation in a vacuum of Torr. Finally, a thin layer of CsF (about 1 nm) covered with aluminum (100 nm) for the bipolar device as the S-3

4 cathode was deposited in a vacuum thermal evaporator through a shadow mask at a vacuum of Torr. The fabrication procedure for single carrier device was similar to that for the bipolar device. The hole dominating device structure was ITO/PEDOT: PSS (35 nm) /90 wt % 26DCzPPy: TAPC or TCTA=8:2 by weight/10 wt % DMAC- TRZ (45 nm)/moo3 (8 nm) /Al (100 nm). The active area (about 8 mm 2 ) and the thickness of device were measured by using a surface profiler Tencor P-10 from KLA. I V characteristics of the devices were measured using a keithley-238 source meter and brightness was measured with a luminance meter BM-8 from TOPCON. The current efficiency of the device in cd A -1 was obtained by dividing brightness by its corresponding current density. S2. The performance characteristics of the devices having 26DCzPPy doped with different weight ratio TCTA. We have carried out experiments covering the weight ratio from 9:1 to 6:4 and found that 8:2 is the optimal ratio as shown in the Table be S1. Table S1. The device performances of 26DCzPPy with various TCTA weight ratio as host. 26DCzPPy:TCTA (wt %:wt %) Von a(b) Bmax ηamax/ηa1000 ηpmax/ηp1000 EQEmax (V) (cd/m 2 ) ( cd/a) ( lm/w) (%) 9: at 9.2 V 27.7/ / : at 9.0 V 33.7/ / : at 8.6 V 25.8/ / : at 8.4 V 21.8/ / a The device structure is ITO/PEDOT:PSS (35 nm)/90 wt % 26DCzPPy:HTM=(10-x):x (wt %:wt %)/10 wt % DMAC-TRZ(45 nm)/tmpypb (50 nm)/csf (1 nm)/al (100 nm). b V on is defined as the voltage at which a luminance of 1 cd/m 2 is reached. S-4

5 Figure S1. The performance characteristics of the devices having 26DCzPPy doped with different weight ratio TCTA as host. (a) current density and brightness versus applied voltage and (b) current and power efficiencies versus luminance. The device structure is ITO/PEDOT:PSS (35 nm)/90 wt % 26DCzPPy:HTM=(10-x):x (wt %:wt %)/10 wt % DMAC-TRZ (45 nm)/tmpypb (50 nm)/csf (1 nm)/al (100 nm). S-5

6 S3. The EL spectra from the device with 26DCzPPy:HTM (8:2 by weight) as the mixed host and TADF material DMAC-TRZ as a blue emission dopant. Figure S2. The EL spectra from the device with 26DCzPPy:HTM (8:2 by weight) as the mixed host and TADF material DMAC-TRZ as a blue emission dopant at 7 V. The device structure is ITO/PEDOT:PSS (35 nm)/90 wt % 26DCzPPy:HTM=8:2 by weight/10 wt % DMAC-TRZ (45 nm) /TmPyPB (50 nm) /CsF (1 nm) /Al (100 nm). S-6

7 S4. The EL spectra from the device with the mixed host 26DCzPPy:TCTA (8:2 by weight) and different contents of DMAC-TRZ as a blue dopant. Figure S3. The EL spectra from the device with the mixed host 26DCzPPy:TCTA (8:2 by weight) and different contents of DMAC-TRZ as a blue dopant at 7 V. The device structure is ITO/PEDOT:PSS (35 nm)/ (100-x) wt % 26DCzPPy:TCTA=8:2 by weight/x wt % DMAC-TRZ (45 nm) /TmPyPB (50 nm) /CsF (1 nm)/al (100 nm). S-7

8 S5. The spectra of EL and PL with different red dopant concentration. Figure S4. The spectra of EL and PL with different red dopant concentration. The electronic device structure of T P hybrid WOLEDs is ITO/PEDOT:PSS (35 nm)/ 90 wt % 26DCzPPy:TCTA=8:2 by weight /10 wt % DMAC-TRZ/x wt % Ir(dpm)PQ2 (45 nm)/tmpypb (50 nm)/csf (1 nm)/al. S-8

9 S CIE coordinates for Blue and the White Organic Light-Emitting Diodes Figure S CIE coordinates for the devices having 26DCzPPy doped with 20 wt % of various hole transport materials as host. The device structure is ITO/PEDOT:PSS (35 nm)/90 wt % 26DCzPPy: HTM=8:2 by weight /10 wt % DMAC-TRZ (45 nm) /TmPyPB (50 nm) /CsF (1 nm) /Al (100 nm). S-9

10 Figure S CIE coordinates for the TADF BOLEDs with different DMAC-TRZ concentrations in wt %. The device structure is ITO/PEDOT:PSS (35 nm)/ 90 wt % 26DCzPPy:TCTA=8:2 by weight/ x wt % DMAC-TRZ (45 nm) /TmPyPB (50 nm)/csf (1 nm)/al (100 nm). S-10

11 Figure S CIE coordinates for the T P hybrid WOLEDs with the red phosphor Ir(dpm)PQ2 or red fluorescent emitter DCJTB. The device structure of hybrid WOLEDs is ITO/PEDOT:PSS (35 nm)/26dczppy:tcta=8:2 by weight /10 wt % DMAC-TRZ/x wt % Red dopant (45 nm)/tmpypb (50 nm)/csf (1 nm)/al. S-11