Highly efficient blue light-emitting diodes based on diarylanthracene/ triphenylsilane compounds

Article abstract of DOI:10.1166/jnn.2011.3698

New host materials have been designed and synthesized, (4-(10-(naphthalen- 2-yl)anthracen-9-yl)phenyl)triphenylsilane (ANPTPS) and (9,9-dimethyl-7-(10- (naphthalen-2-yl)anthracen-9-yl)-9Hfluoren-2-yl)triphenylsilane (ANFTPS), and photophysical characteris

Full text of DOI:10.1166/jnn.2011.3698

Copyright © 2011 American Scientific Publishers
All rights reserved
Printed in the United States of America
Journal of
Nanoscience and Nanotechnology
Vol. 11, 4357–4362, 2011
Highly Efficient Blue Light-Emitting Diodes Based on
Diarylanthracene/Triphenylsilane Compounds
Jeong Keun Park1, Kum Hee Lee1, Jung Sun Park2, Ji Hoon Seo2,
Young Kwan Kim2ꢀ∗, and Seung Soo Yoon1ꢀ∗
1Department of Chemistry, Sungkyunkwan University, Suwon 440-746, Korea
2Department of Information Display, Hongik University, Seoul 121-791, Korea
New host materials have been designed and synthesized, (4-(10-(naphthalen-2-yl)anthracen-
9-yl)phenyl)triphenylsilane (ANPTPS) and (9,9-dimethyl-7-(10-(naphthalen-2-yl)anthracen-9-yl)-9H-
fluoren-2-yl)triphenylsilane (ANFTPS), and photophysical characteristics investigated to determine
suitability as candidates for blue light-emitting materials. To explore the electroluminescent prop-
erties, multilayered OLEDs were fabricated with the device structure of ITO/NPB/Host (ANPTPS
and ANFTPS): 8% Dopant (PFVtPh and PCVtPh)/Bphen/Liq/Al. By using a host (ANPTPS) and a
dopant (PFVtPh) as the emitting layer, high-efficiency blue OLEDs were fabricated with a maximum
luminance of 3991 cd/cm2 at 8.0 V, a luminous efficiency of 5.99 cd/A at 20 mA/cm2, a power
efficiency of 3.11 lm/W at 20 mA/cm2, an external quantum efficiency of 4.13% at 20 mA/cm2, and
CIExꢀy coordinates of (x = 0ꢁ15, y = 0ꢁ18) at 8.0 V.
Keywords: Blue OLED, Host Material, Diarylanthracene, Triphenylsilane, Suzuki Cross-Coupling
Reaction.Delivered by Ingenta to: McMaster University
IP: 91.242.217.252 On: Sat, 11 Jun 2016 10:14:39
Copyright: American Scientific Publishers
1. INTRODUCTION
(CIE coordinates (y-coordinate value < 0ꢀ15)) are
still rare.
Subsequent to the achievements of the Kodak group,
organic light-emitting diodes (OLEDs) have shown great
potential as a technology for the next generation of flat-
panel displays.1 The search and discovery of stable and
highly efficient three primary colors (red, green, blue)
emitters are important for OLEDs to become commer-
cial products.2 Among the important research subjects
regarding OLEDs, the hunt for blue-light emitting mate-
rials and devices is of particular interest as they are
essential components in realizing full-color displays and
as solid-state lighting. Additionally, blue emitters can
be utilized to generate green or red light through an
energy cascade to a suitable emissive material.3 It is
well-known that a dopant–host doped emitter system can
significantly improve device performance in terms of
EL efficiency and emissive color.4 Various material sys-
tems have been reported as blue host materials, includ-
ing anthracene,5 di(styryl)arylene,6 tetra(phenyl)pyrene,7
oligofluorenes,8 and tetra(phenyl)silyl derivatives.9 How-
ever, blue-light emitting materials with high efficiency
and excellent Commission Internationale de l’Énclairage
In this paper, the synthesis, characterization, and inves-
tigation of new, highly efficient blue host materials by
making use of diarylanthracene-containing triphenylsilane
moieties are reported. Two blue host materials, (4-(10-
ꢁnaphthalen- 2 -ylꢂanthracen- 9 -ylꢂphenylꢂtriphenylsilane
(ANPTPS) and 9,9-dimethyl-(7-(10-(naphthalen-2-yl)anth-
racen-9-yl)-9H-fluoren-2-yl)triphenylsilan(ANFTPS), are
based on a 9-naphthylanthracene core with triphenylsi-
lylbenzene and triphenylsilyl-9,9-dimethyl-9H-fluorene
at the 10-position of the anthracene moiety. In these
host materials, the 9-naphthylanthracene core derivatives
provide excellent thermal- and electrochemical stabili-
ties, as well as good photoluminescent properties to new
host materials.10ꢃ11 The silicone moiety can prevent inter-
molecular interactions of the host materials through steric
hindrance of the nonplanar silicon moieties and reduce
the self-quenching effect between the host materials. In
addition, the role of the silicon moieties in forming ther-
mally stable and pin-hole free amorphous thin films was
demonstrated,12 thus contributing to the high efficiency of
the blue OLED devices. As will be seen, using these new
blue host materials, the blue OLEDs with a high efficiency
are demonstrated.
∗Authors to whom correspondence should be addressed.
J. Nanosci. Nanotechnol. 2011, Vol. 11, No. 5
1533-4880/2011/11/4357/006
doi:10.1166/jnn.2011.3698
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Highly Efficient Blue Light-Emitting Diodes Based on Diarylanthracene/Triphenylsilane Compounds
Park et al.
2. EXPERIMENTAL DETAILS
(75 MHz, CDCl3) [ꢄ ppm]: 154.6, 153.5, 140.8, 138.8,
138.6, 138.0, 137.2, 136.8, 135.8, 134.8, 133.7, 133.3,
133.0, 130.7, 130.5, 130.4, 130.3, 129.9, 128.4, 128.2,
127.4, 126.7, 126.5, 126.1, 125.4, 120.5, 119.9, 47.4, 27.5.
FT-IR [ATR]: ꢅ = 3067, 2969, 1738, 1429, 1110, 819, 766,
746, 701 cm−1. EI-MS (m/z): 754 [M+]; HRMS: [EI+]
calcd for C57H42Si: 754.3056, [M+]. Found: 754.3065.
2.1. Material and Measurements
All reactions were performed under nitrogen. Solvents
were carefully dried and distilled from appropriate drying
agents prior to use. 4ꢀ-[2-(2-Diphenylamino-9,9-diethyl-
9H-fluoren-7-yl)vinyl]-p-terphenyl (PFVtPh) and 3-(N-
phenylcarbazol)vinyl-p-terphenyl (PCVtPh) were prepared
by a method previously reported.13
2.3. Physical Measurements
1H- and 13C-NMR were recorded on a Varian Unity
Inova 300Nb spectrometer. FT-IR spectra were recorded
using a Bruker VERTEX70 FT-IR spectrometer. Low-
resolution mass spectra were measured using a Jeol
JMS-AX505WA spectrometer in the FAB mode or a Jeol
JMS-600 spectrometer in the EI mode.
The UV-Vis absorption and photoluminescence spectra of
these newly designed host materials were measured in
CH2Cl2 (10−5 M) using a Shimadzu UV-1650PC and an
Amincobrowman series 2 luminescence spectrometer. The
fluorescent quantum yields were determined in the CH2Cl2
solution at 293 K against the host (ꢆDPA = 0ꢀ90) as a
reference. The energy levels were measured with a low-
energy photo-electron spectrometer (Riken-Keiki, AC-2).
Thermal properties were measured using thermogravimet-
ric analysis (TGA) (Seiko, TG/DTA 320) under nitrogen
2.2. General Procedure for the Suzuki
Cross-Coupling Reaction
10-(Naphthalen-2-yl)anthracen-9-yl-boronic acid (1.2 mol)
and the corresponding triphenylsilyl bromide derivatives
(1.0 mol), Pd(PPh3ꢂ4 (0.04 mol), aqueous 2.0 M Na2CO3
(10.0 mol), ethanol, and toluene were mixed in a flask. The
mixture was refluxed for 4 h. After the reaction had fin-
ished, the reaction mixture was extracted with ethyl acetate
and washed with water. The organic layer was dried with
ꢁ
at a heating rate of 10 C/min.
2.4. OLED Fabrication and Measurement
For fabricating OLEDs, indium-tin-oxide (ITO) thin
films coated on glass substrates were used, which was
30 ꢇ/square of the sheet resistivity, and 1000 Å of thick-
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anhydrous MgSO4 and filtered with silica gel. The solution
ness. The ITO-coated glass was cleaned in an ultrasonic
IP: 91.242.217.252 On: Sat, 11 Jun 2016 10:14:39
was then evaporated. The crude product was then recrys-
tallized from CH2Cl2/EtOH and then purified further by
train sublimation at the reduced pressure.
Copyright: American Scientific Publishers
bath by the following sequence: acetone, methyl alco-
hol, distilled water, and stored in isopropyl alcohol for
48 h and dried by a N2 gas gun. The substrates were
treated by O2 plasma under 2ꢀ0 × 10−2 torr at 125 W for
2 min.14 All organic materials and metals were deposited
under high vacuum (5×10−7 torr). The OLEDs were fabri-
cated in the following sequence: ITO/N,Nꢀ-diphenyl-N,Nꢀ-
(1-napthyl)-(1,1ꢀ-phenyl)-4,4ꢀ-diamine (NPB) (500 Å)/Blue
host materials (ANPTPS and ANFTPS): Blue dopant mate-
rials (PFVtPh and PCVtPh) (300 Å, 8%)/4,7-diphenyl-
1,10-phenanthroline (Bphen) (300 Å)/lithium quinolate
(Liq) (20 Å)/Al (1000 Å). The devices were fabricated with
the same configurations, except employing 8% PFVtPh
and PCVtPh as a dopant within ANPTPS and ANFTPS
as a host in the emitting layers. The current density (J),
luminance (L), luminous efficiency (LE), and CIE chro-
maticity coordinates of the OLEDs were measured with a
Keithly 2400, Chroma meter CS-1000A. Electroluminance
was measured using a Roper Scientific Pro 300i.
2.2.1. (4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)
triphenylsilane (ANPTPS)
1
Yield: 70%, H-NMR (300 MHz, CDCl3) [ꢄ ppm]: 8.06
(d, J = 8ꢀ1 Hz, 1H), 8.03–8.00 (m, 1H), 7.98 (s, 1H), 7.92–
7.89 (m, 1H), 7.83 (d, J = 8ꢀ4 Hz, 2H), 7.77–7.71 (m, 9H),
7.62–7.55 (m, 4H), 7.54–7.43 (m, 10H), 7.38–7.27
(m, 5H). 13C-NMR (75 MHz, CDCl3) [ꢄ ppm]: 140.7,
137.3, 137.2, 136.8, 136.7, 134.5, 133.7, 133.6, 133.0,
131.1, 130.5, 130.3, 130.0, 129.9, 129.8, 128.4, 128.3,
128.2, 128.1, 127.3, 126.7, 126.5, 125.4. FT-IR [ATR]:
ꢅ = 3066, 1428, 1109, 818, 766, 745, 702 cm−1. FAB-
MS (m/z): 638 [M+]; HRMS: [EI+] calcd for C48H34Si:
638.2430, [M+]. Found: 638.2438.
2.2.2. 9,9-dimethyl-7-(10-(naphthalen-2-yl)
anthracen-9-yl)-9H-fluoren-2-yl)triphenylsilane
(ANFTPS)
3. RESULTS AND DISCUSSION
1
Yield: 60%, H-NMR (300 MHz, CDCl3) [ꢄ ppm]: 8.08
Scheme 1 shows the Synthesis of the newly designed
host compounds and the structure of dopant compounds.
The host compounds were synthesized via Suzuki Cross-
Coupling reactions with moderate yields. All the obtained
compounds were characterized by 1H- and 13C NMR,
(d, J = 8ꢀ4 Hz, 1H), 8.05–7.97 (m, 3H), 7.94–7.91
(m, 1H), 7.86 (d, J = 7ꢀ2 Hz, 1H), 7.82–7.79 (m, 2H),
7.75–7.71 (m, 3H), 7.66–7.58 (m, 11H), 7.50–7.37
(m, 10H), 7.35–7.30 (m, 4H), 1.53 (s, 6H). 13C-NMR
4358
J. Nanosci. Nanotechnol. 11, 4357–4362, 2011

Park et al.
Highly Efficient Blue Light-Emitting Diodes Based on Diarylanthracene/Triphenylsilane Compounds
Host
(a)
B(OH)2
+
Br
Si
Si
ANPTPS
(a)
Si
Si
B(OH)2 + Br
ANFTPS
Dopant
N
N
PCVtPh
PFVtPh
Scheme 1. Synthesis of the newly designed host compounds and the structure of dopant compounds. Conditions: (a) Pd(PPh3ꢂ4, 2 M Na2CO3,
Toluene/EtOH, reflux, 4 h.
FT-IR, and low-resolution mass spectroscopy. High-
pressure liquid chromatography (HPLC) analysis was car-
ried out to verify purity of materials. These analyses
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revealed that the purity of theIPb:lu9e1-.e2m4i2tt.i2n1g7.m25at2erOianls: Sat, 11 Jun 2016 10:14:39
(ANPTPS and ANFTPS) were at least above 99.5%.
ANPTPS
ANFTPS
(a)
Copyright: American Scienti1fi.c0 Publishers
Figure 1 shows the UV-Vis absorption (a) and photo-
0.8
luminescence (b) spectra of host compounds (ANPTPS
0.6
and ANFTPS) in CH2Cl2 solution. In the UV-Vis absorp-
tion spectra, the maximum absorption wavelengths (ꢈmax
)
0.4
0.2
0.0
of ANPTPS and ANFTPS appeared at ꢈmax = 377 and
378 nm, respectively. In the PL spectra, the maximum
emission wavelengths (ꢈmaxꢂ of ANPTPS and ANFTPS
appeared at ꢈmax = 422 and 425 nm, respectively, in the
deep blue region of the visible spectrum. Compared to
the PL spectra of ANPTPS, those of ANFTPS showed
a 3 nm red shift due to the lengthening ꢉ-conjugation
caused by the structural difference of the spacers between
the 10-naphthylanthracene and triphenylsilane.
The thermal properties of ANPTPS and ANFTPS were
determined by thermogravimetric analysis (TGA), with the
results summarized in Table I. Two host materials showed
excellent thermal stabilities. For example, thermal analysis
of ANPTPS and ANFTPS revealed high thermal stability.
The decomposition points (Td) from the onset of mass loss
using TGA were near 389.6 ꢁC for ANPTPS and 429.4 ꢁC
for ANFTPS.
330 345 360 375 390 405 420 435
Wavelength (nm)
Abs.
PL
ANPTPS-PL
ANFTPS-PL
PFVtPh-Abs.
PCVtPh-Abs.
(b)
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
Table I shows the HOMO and the LUMO energy lev-
els of the host materials. The HOMO energy levels of
ANPTPS and ANFTPS were −5.77 and −5.85 eV, respec-
tively as measured by a low-energy photo-electron spec-
trometer (Riken-Keiki AC-2). The optical energy band
300
350
400
450
500
550
Wavelength (nm)
Fig. 1. (a) UV-Vis absorption and (b) PL emission spectra of the host
and dopant materials.
J. Nanosci. Nanotechnol. 11, 4357–4362, 2011
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Highly Efficient Blue Light-Emitting Diodes Based on Diarylanthracene/Triphenylsilane Compounds
Table II. EL performance characteristic of Devices 1–4.
Park et al.
Table I. Optical properties of host materials (ANPTPS and ANFTPS).
Device
1
2
3
4
Compound
ANPTPS
ANFTPS
Td [ꢁC]
389.6
377
422
429.4
378
425
a
ELmax [nm]
Vturn-on [V]
455
4.0
454
3.7
436
3.2
442
2.9
a
b
UVmax [nm]
PLmax [nm]
Lb [cd/m2]
Jc [mA/cm2]
LEd [cd/A]
PEe [lm/W]
QEf [%]
3991
177.1
5.59
3.11
4.13
5556
192.9
5.05
2.66
3.36
558
97.0
1.05
0.43
1.35
2247
176.1
2.22
1.33
1.95
c
FWHM [nm]
HOMOd [eV]
LUMOd [eV]
Eg [eV]
53
54
−5.77/
−2.72
3.05
0.86
−5.85/
−2.84
3.01
0.75
CIEg (xꢃy)
(0.15, 0.18) (0.16, 0.18) (0.16, 0.09) (0.17, 0.12)
ꢆe
aDecomposition points Td from onset of mass loss using TGA. with a heating rate of
10 ꢁC min−1 under N2. bꢃcMaximum absorption or emission wavelength, measured
in CH2Cl2 solution. dObtained from AC-2 and UV-Vis absorption measurements.
eUsing DPA as a standard; ꢈex = 360 nm (ꢆ = 0ꢀ90 in CH2Cl2).
Note: Device (ITO/NPB/EML (host-dopant)/Bphen/Liq/Al): 1. ANPTPS-PFVtPh,
2. ANFTPS-PFVtPh, 3. ANPTPS-PCVtPh, 4. ANFTPS-PCVtPh. aTurn-on voltage,
bꢃcThe luminance and current density, dꢃeꢃf The luminous, power and quantum effi-
ciency at 20 mA/cm2, gCommission Internationale d’Énclairage (CIE) coordinates
at a 8.0 V.
gaps (Eg) of ANPTPS and ANFTPS were 3.05 and
3.01 eV, as determined from the absorption spectra. The
LUMO energy levels of ANPTPS and ANFTPS, calculated
as the difference between the HOMO levels and optical
energy band gaps (Eg), were −2.72 and −2.84 eV, respec-
tively. Figure 2 shows the HOMO and LUMO energy lev-
els of the host and dopant materials, along with the other
materials used in electroluminescence devices, including:
ITO; NPB; MADN; Bphen; Liq:Al.
1–2 which appeared at the longer wavelength (∼480 nm)
compared to the dopant emissions (∼455 nm). How-
ever, the possibilities of the emissions originated from the
exciplexes16 between dopant PFVtPh and hosts in solid
state devices could not be excluded. The corresponding
CIE coordinates at 8.0 V were (0ꢀ15ꢃ0ꢀ18) for device 1,
(0ꢀ16ꢃ0ꢀ18) for device 2, (0ꢀ16ꢃ0ꢀ09) for device 3, and
(0ꢀ17ꢃ0ꢀ12) for device 4, respectively. Figure 4 gives the
luminance (L)–voltage (V)–current density (J) characteris-
tics of devices 1–4. All devices showed low turn-on volt-
ages no greater than 4.0 V. The maximum luminances
and current densities of devices 1–4 were (3991 cd/m2,
177.1 mA/cm2), (5556 cd/m2, 192.9 mA/cm2), (558 cd/m2,
97.0 mA/cm2), and (2247 cd/m2, 176.1 mA/cm2), respec-
tively. These observations suggest that the carrier injection
into the emitting layer of devices using ANFTPS as a host
was more effective than those using ANPTPS as a host.
Interestingly, comparing devices 2 and 4 using the same
material ANFTPS, the current density of device 4 using
PCVtPh as a dopant was higher than that of device 2 using
PFVtPh as a dopant. This observation implies that the
dopant materials play significant roles in electronic prop-
erties of OLED devices. Presumably, the dopant PFVtPh
in device 2 act as the effective hole trap because HOMO
energy level of PFVtPh is higher than that of PCVtPh in
To explore the electroluminescent properties of these
molecules, the devices were fabricated and the results
summarized in Table II. The EL emission spectra of
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devices 1–4, with the emitting layer consisting of the
IP: 91.242.217.252 On: Sat, 11 Jun 2016 10:14:39
host (ANPTPS and ANFTPS) doped with 8% dopant
Copyright: American Scientific Publishers
(PFVtPh and PCVtPh), are seen in Figure 3. All devices
exhibited blue emissions with the maximum emission
peaks of 436–455 nm. Comparing the devices 1–2 and
3–4, the EL emission of devices 3–4 were blue-shifted
due to the difference of energy band gaps (Eg) for the
dopant materials PFVtPh (2.8 eV) and PCVtPh (3.1 eV).
Interestingly, the EL spectra of devices 1–2 showed the
shoulder peaks around 480 nm. Dopant PFVtPh of devices
1–2 has the large aromatic surface composed of fluorene
and terphenyl moieties and thus has chance to form inter-
molecular aggregates through ꢉ–ꢉ stacking interactions.
This would lead to the excimer emissions15 of devices
1.0
0.8
0.6
0.4
0.2
0.0
Device 1
Device 2
Device 3
Device 4
(a)
(b)
400
450
500
550
600
650
Wavelength (nm)
Fig. 3. EL spectra of the devices 1–4.
J. Nanosci. Nanotechnol. 11, 4357–4362, 2011
Fig. 2. Energy diagram of (a) devices 1–2 and (b) devices 3–4.
4360

Park et al.
Highly Efficient Blue Light-Emitting Diodes Based on Diarylanthracene/Triphenylsilane Compounds
9
8
7
6
5
4
3
2
1
(a)
(a)
6000
Device 1
Device 2
Device 3
Device 4
Device 1
Device 2
Device 3
Device 4
5000
4000
3000
2000
1000
0
2
4
6
8
10
0
20
40
60
80
100
Voltage (V)
Current density (mA/cm2)
8
7
6
5
4
3
2
1
0
(b)
(b)
200
150
100
50
Device 1
Device 2
Device 3
Device 4
Device 1
Device 2
Device 3
Device 4
0
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0
20
40
60
80
100
120
140
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2
4
6
10
Current density (mA/cm2)
Voltage (V)
Copyright: American Scientific Publishers
(c)
Fig. 4. (a) L–V characteristics and (b) J–V characteristics of the
devices 1–4.
6
5
4
3
2
1
0
Device 1
Device 2
Device 3
Device 4
device 4. This effective hole trapping would lead to the
lower current density in device 2.
Figure 5 shows the luminous efficiencies, power effi-
ciencies, and quantum efficiencies as a function of cur-
rent density for the devices 1–4. The luminous efficiencies,
power efficiencies, and quantum efficiencies of devices
1–4 were (5.39 cd/A, 3.11 lm/W, 4.13%), (5.05 cd/A,
2.66 lm/W, 3.36%), (1.05 cd/A, 0.43 lm/W, 1.35%), and
(2.22 cd/A, 1.33 lm/W, 1.95%) at 20 mA/cm2, respec-
tively. An OLED device 1 with the color coordinate of
(x = 0ꢀ15, y = 0ꢀ18) exhibited the best performance with
luminance, power, and external quantum efficiencies of
5.39 cd/A, 3.11 lm/W, and 4.13% at 20 mA/cm2, respec-
tively. Interestingly, devices 1–2 exhibited much higher
efficiencies than devices 3–4 due to the difference of an
overlap between host materials (ANPTPS and ANFTPS)
and dopant materials (PFVtPh and PCVtPh). It can be
seen from Figure 1(b) that the PL spectra of the host
materials (ANPTPS and ANFTPS) overlapped better with
the absorption spectra of dopant PFVtPh than those of
dopant PCVtPh, demonstrating that PFVtPh can effec-
tively accept energy from the host materials (ANPTPS
and ANFTPS) through Förster-type energy transfer.17 This
0
20
40
60
80
100
120
140
Current density (mA/cm2)
Fig. 5. (a) Luminous efficiencies, (b) power efficiencies, and (c) quan-
tum efficiencies as a function of current density for the devices 1–4.
effective energy transfer would lead the improved EL effi-
ciencies of devices 1–2. In devices 3–4, the Förster energy
transfer from host to dopants is not effective because of
the wider band-gap of dopant than those of hosts and
the small overlap between PL spectra of hosts and the
absorption spectra of dopant PCVtPh. Also, electron trap-
ping into dopants in devices 3–4 would be ineffective due
to the quite high LUMO energy level of dopant com-
pared to those of host and ETL material. However, the
J. Nanosci. Nanotechnol. 11, 4357–4362, 2011
4361

Highly Efficient Blue Light-Emitting Diodes Based on Diarylanthracene/Triphenylsilane Compounds
Park et al.
electroluminescence of devices 3–4 can be explained by
the endothermic energy transfer18 from hosts to dopant
PCVtPh. In this system, the confinement of excitons in
dopants is not effective due to the smaller band-gap energy
of hosts than dopant. Thus devices 3–4 exhibited not only
an emission of dopant but also hosts. Also, compared to
devices 1–2 in which are possible the exothermic energy
transfer, the EL efficiencies of devices 3–4 are decreased
because of the interferences of the low efficient host emis-
sions. Therefore, this study clearly suggests that the effi-
cient energy transfer between host and dopant plays an
important role in OLED efficiency.
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4. CONCLUSIONS
Host materials based on diarylanthracene with triphenylsi-
lane moieties have been newly designed and synthesized
via the Suzuki Cross-Coupling reaction. By using host
(ANPTPS) and dopant (PFVtPh) in the emitting layer,
high-efficiency blue OLEDs were fabricated, showing a
maximum luminance of 3991 cd/cm2 at 8.0 V, a luminous
efficiency of 5.99 cd/A at 20 mA/cm2, a power efficiency
of 3.11 lm/W at 20 mA/cm2, an external quantum effi-
ciency of 4.13% at 20 mA/cm2, and CIEx,y coordinates
of (x = 0ꢀ15, y = 0ꢀ18) at 8.0 V. This study clearly sug-
gests that diarylanthracene derivatives with triphenylsilane
moieties have excellent properties for blue host materials
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Delivered by Ingenta to: McMaster University
Park, G. Y. Kim, J. H. Seo, Y. K. Kim, and S. S. Yoon, J. Nanosci.
for OLEDs.
IP: 91.242.217.252 On: Sat, 11 Jun 2016 10:14:39
Nanotechnol. 10, 3289 (2009).
Copyright: American Scientific Publishers
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Acknowledgment: This research was supported by
Basic Science Research Program through the National
Research Foundation of Korea (NRF) funded by
the Ministry of Education, Science and Technology
(20090073679).
References and Notes
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2. L. S. Hung and C. H. Chen, Mater. Sci. Eng. R 39, 143 (2002).
Received: 22 May 2009. Accepted: 20 November 2009.
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