ELECTROLUMINESCENCE OF A DEVICE BASED
ON A NEW TERBIUM β-DIKETONATE COMPLEX
A.Pereira1,G. Conte2, H. Gallardo2, W. G. Quirino3, K. C. Teixeira3,
C. Legnani3 M. Cremona3, 4 and I. H. Bechtold1
1Department
3
of Physics and 2Department of Chemistry, UFSC
LADOR– Laboratory of Organic Devices, Inmetro
4 Department of Physics,PUC-RJ
Laboratório de Sistemas
Anisotrópicos
E-mail: [email protected]
OLED Technology:
Motivation:

The use of trivalent rare earth ions complexes containing
organic moiety is a possible route to obtain pure color
emission with a theoretical upper limit of inner quantum
efficiency near 100%.

These complexes emit with a narrow emission spectrum
characteristic of intra-atomic transitions of the central
rare earth ion, covering the spectral range from
ultraviolet to infrared, which make them with organic
ligands candidates for full color OLEDs applications.
Objectives:
To check the feasibility of using a novel Terbium
complex as electroluminescent layer.
Materials:
The structures of the complexes. (a) Tb(N-PA)3Phen and
Tb(N-PA)3Bipy; (b) Tb(FURA)3Phen and Tb(FURA)3Bipy.
([1,2,5]tiadiazol[3,4f][1,10]fenantrolina)
complex-Tb (acetilacetona-ACAC)
Hole transport molecule
Y. Fu et al(2008).
Experimental setup:
LADOR-INMETRO
OLED bilayer
The devices were fabricated with the following structure:
ITO/NPB(50nm)/Complex-Tb(50nm)/Al(150nm).
300
400
500
600
Wavelenght (nm)
5
7
D4 F5
7
D4 F6
1.0
0.8
5
0.2
5
7
7
D4 F4
0.4
D4 F3
0.6
5
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
200
Normalized Intensity(arb.un.)
Normalized Absorbance(arb. un.)
Characterization:
0.0
450
500
550
600
650
Wavelenght (nm)
Absorption spectrum at room temperature
from thin films of Terbium complex.
Photoluminescence spectra at room
temperature from thin films of Terbium
complex.
Characterization:
6
0,001
Counts
Current (A)
0,002
0,000
0
5
10
15
20
25
Voltage (V)
IxV plot, from OLED based on a new Terbium complex
as a function of bias voltage.
Picture of a
produced OLED.
1x10
6
1x10
5
9x10
5
8x10
5
7x10
5
6x10
5
5x10
5
4x10
5
3x10
5
2x10
5
1x10
0
5
-1x10
6V
8V
10V
12V
14V
16V
18V
20V
22V
400
450
500
550
600
650
700
Wavelenght (nm)
Electroluminescence spectra of the Terbium
complex.
Orange!!!
Conclusions and perspectives:
The electroluminescence spectrum shows two large
bands resulting an orange light emission, which was not
observed in the photoluminescence. It indicates a
possible problem in the charge transport or in the
manufacturing architecture.
The device shows a typical diode behavior with a low
threshold bias voltage of about 10V.
To investigate the observed effect in the
electroluminescence:
- ligands contribution
- OLED architecture
Financial Supports:
INEO – Instituto Nacional de Eletrônica
Orgânica