Supplementary Information: White OLEDs with 4 nm Metal Electrode
Simone Lenk1, Tobias Schwab1, Sylvio Schubert1, Lars Müller-Meskamp1, Karl Leo1,
Malte C. Gather1,2 and Sebastian Reineke1
1Institut
für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Straße 1,
01069 Dresden, Germany
2Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews,
North Haugh, St Andrews KY16 9SS, United Kingdom
8
ITO
Ag
6 nm
4 nm
2 nm
z / nm
6
4
2
0
-2
0.8
0.6
0.4
0°
10°
20°
30°
40°
50°
60°
70°
80°
0.2
0.0
0.8
0.6
0.4
400 450 500 550 600 650 700 750
wavelength / nm
4 nm
0°
10°
20°
30°
40°
50°
60°
70°
80°
0.2
0.0
400 450 500 550 600 650 700 750
wavelength / nm
norm. radiant intensity / a.u.
1.0
ITO
5
1.0
norm. radiant intensity / a.u.
norm. radiant intensity / a.u.
norm. radiant intensity / a.u.
10
15
20
x / µm
Fig. S1: Profilometer scans of the metal layers (3 nm MoO3/2 nm Au/ x nm Ag) and ITO on glass.
1.0
0
1.0
2 nm
0.8
0.6
0.4
0°
10°
20°
30°
40°
50°
60°
70°
80°
0.2
0.0
0.8
0.6
0.4
400 450 500 550 600 650 700 750
wavelength / nm
6 nm
0°
10°
20°
30°
40°
50°
60°
70°
80°
0.2
0.0
400 450 500 550 600 650 700 750
wavelength / nm
Fig. S2: Spectrally resolved angular dependent emission characteristics at 15 mA/cm² of the OLEDs under study.
~1~
ITO
0.46
Ag
0 nm
2 nm
4 nm
6 nm
8 nm
CIE y
0.44
0.42 80° 80°
0°
80°
A 80°
0.40
0°
0°
0° 0°
80°
0.38
0.40
0.42
0.44
0.46
0.48
0.50
0.52
CIE x
Fig. S3: Simulated CIE color shifts of white OLEDs with different Ag layer thickness. The angular dependent
CIE color shift from 0° to 80° is indicated with a black arrow.
In order to investigate the angular dependent emission characteristics, optical simulations are
performed. These simulations are based on the point dipole model to describe radiative
molecular transitions and on the transfer matrix approach for the calculation of the
electromagnetic field in planar OLED structures [M. Furno et al., Proc. SPIE 7617, 761716
(2010) & M. Furno et al., Phys. Rev. B 85, 115205 (2012)]. As device input, the experimental
architecture as shown in Fig. 1(a) is used. For the electrodes with Ag, the MoO3 layer has
been omitted in the simulation, since it is expected to play minor role. The fraction of emitter
contribution (red, green, and blue) was obtained by fitting the 0° spectrum of the ITO-OLED
and kept constant for all other devices. The obtained CIE color coordinates of the different
viewing angles are shown in Fig. S3. The simulated CIE coordinates vary slightly from the
experimental data shown in Fig. 2(c), but the main trends can be reproduced. For example, the
angular color stability deteriorates with increasing Ag thickness. Furthermore, a thicker Ag
layer leads to a shift to larger xCIE coordinates, which is again in agreement with the
experiment. According to the simulation, a device without Ag layer would have an even lower
angular dependent CIE color shift. However, in practice a layer thickness of 2 nm Ag is the
minimum required to obtain sufficient conductivity and functional OLEDs.
norm. luminance / a.u.
1.0
ITO
Ag
6 nm
4 nm
2 nm
0.9
0.8
0.7
10 mA/cm²
0.6
0.5
0.4
0.3
0
5
10
15
20
time / h
Fig. S4. Lifetime of the OLEDs under study at 10 mA/cm².
~2~