Artículo Oled

Multilayered graphene used as anode of organic light emitting devices
T. Sun, Z. L. Wang, Z. J. Shi, G. Z. Ran, W. J. Xu et al.
Citation: Appl. Phys. Lett. 96, 133301 (2010); doi: 10.1063/1.3373855
View online: http://dx.doi.org/10.1063/1.3373855
View Table of Contents: http://apl.aip.org/resource/1/APPLAB/v96/i13
Published by the American Institute of Physics.

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APPLIED PHYSICS LETTERS 96,133301 2010

Multilayered graphene used as anode of organic light emitting devices
T. Sun,1 Z. L. Wang,1 Z. J. Shi,2 G. Z. Ran,1 W. J. Xu,1 Z. Y. Wang,2 Y. Z. Li,1 L. Dai,1,a
and G. G. Qin1,a
1

State Key Laboratory for Microscopic Physics, School of Physics, Peking University, Beijing 100871,
People’s Republic of China
2
Beijing National Laboratory for Molecular Sciences, State Key Lab of RareEarth Materials Chemistry and
Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871,
People’s Republic of China

Received 29 January 2010; accepted 4 March 2010; published online 29 March 2010
In this report, we find multilayered graphene, which has good transparency, conductivity and
suitable work function, can be used as the anode for the organic lightemitting device. Our
device structure is Al/glass/multilayered graphene / V2O5 / NPB / CBP: ppy 2Ir acac / Bphen /
Bphen: Cs2CO3 / Sm / Au. The maximum luminance efficiency and maximum power efficiency reach
0.75 cd/A and 0.38 lm/W, respectively. We believe that by optimizing the hole density and
uniforming the thickness of the multilayered graphene anode, the device efficiency can be
remarkablyincreased in the future. © 2010 American Institute of Physics. doi:10.1063/1.3373855
Today organic light emitting devices OLEDs are
widely used in display and illumination. The OLEDs are
easier to be made than III-V compounds light emitting diodes LEDs . So far indium tin oxide ITO has been widely
used as the anode material for the OLEDs. ITO has the merits of good light transparency, conductivity,and stability.
However, indium, the component element in ITO, is rare in
earth. From the view of long-term strategy, exploring electrode materials is important in order to further improve the
efficiency and reduce the cost of the OLEDs. Graphene has
very high carrier mobility, and remarkable conductivity and
transparency.1,2 It has potential application in making
electronic3–5 and optoelectronicdevices.6,7 Besides, the sheet
resistance of multilayered graphene can be adjusted by
doping8 or changing the number of the layers. Moreover,
carbon is much richer and cheaper than indium and the work
function 4.6 eV Ref. 9 of graphene is very close to that
of ITO
4.8 eV . Very recently, carbon nanotube films
have been used as anodes for OLEDs.10,11 In this paper, we
report the OLED withmultilayered graphene as the anode.
The multilayered graphene used in this work was grown
by chemical vapor deposition. To prepare the substrate, a 500
nm Ni film was deposited on Si / SiO2 substrates by direct
current magnetron sputtering Gamma 1000C sputtering system as the catalyst. The as-prepared substrates were placed
onto a quartz boat, which was then inserted into the center of
a quartz tube placedin a tube furnace. The furnace was
heated to 1000 ° C in 40 min under an Ar atmosphere. When
the temperature reached 1000 ° C, the samples were annealed
for 20 min in a H2 atmosphere to get rid of the top NiOx
layer on the Ni film. Then a reaction gas mixture of CH4, H2,
and Ar was let into the quartz tube for 3 min under a flow
rate of 25, 250, and 200 SCCM standard cubic centimeter
per minute ,...