ELECTROLUMINESCENCE OF A DEVICE BASED ON A NEW TERBIUM β-DIKETONATE COMPLEX
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ELECTROLUMINESCENCE OF A DEVICE BASED ELECTROLUMINESCENCE OF A DEVICE BASED
ON A NEW TERBIUM ON A NEW TERBIUM β-DIKETONATE COMPLEXβ-DIKETONATE COMPLEX
A.PereiraA.Pereira11,G. Conte,G. Conte22, H. Gallardo, H. Gallardo22, W. G. Quirino, W. G. Quirino33, K. C. , K. C. TeixeiraTeixeira33, C. Legnani, C. Legnani33 M. CremonaM. Cremona3, 43, 4 and I. H. Bechtold and I. H. Bechtold11
11Department of Physics and and 22Department of Chemistry, UFSCDepartment of Chemistry, UFSC 33 LADOR– Laboratory of Organic Devices, Inmetro
4 Department of Physics,PUC-RJ
Laboratório de Sistemas Anisotrópicos
E-mail: [email protected]
OLED Technology:OLED Technology:
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.
Motivation:Motivation:
Objectives:Objectives:
To check the feasibility of using a novel Terbium complex as electroluminescent layer.
Materials:Materials:
The structures of the complexes. (a) Tb(N-PA)3Phen and Tb(N-PA)3Bipy; (b) Tb(FURA)3Phen and Tb(FURA)3Bipy.
N N
NS
N
TbO
O
O O
O
O
([1,2,5]tiadiazol[3,4f][1,10]fenantrolina) complex-Tb (acetilacetona-ACAC)
Hole transport molecule
Y. Fu et al(2008).
Experimental setup:Experimental setup:
The devices were fabricated with the following structure:
ITO/NPB(50nm)/Complex-Tb(50nm)/Al(150nm).
OLED bilayer
LADOR-INMETROLADOR-INMETRO
Characterization:Characterization:
200 300 400 500 6000.00.10.20.30.40.50.60.70.80.91.0
No
rma
lize
d A
bso
rba
nce
(arb
. un
.)
Wavelenght (nm) 450 500 550 600 650
0.0
0.2
0.4
0.6
0.8
1.0
5 D4
7 F3
5 D4
7 F4
5D47F
5
5 D4
7 F6
Nor
mal
ized
Inte
nsity
(arb
.un.
)
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:Characterization:
0 5 10 15 20 25
0,000
0,001
0,002
Cu
rre
nt
(A)
Voltage (V) 400 450 500 550 600 650 700-1x105
01x1052x1053x1054x1055x1056x1057x1058x1059x1051x1061x106
Cou
nts
Wavelenght (nm)
6V 8V 10V 12V 14V 16V 18V 20V 22V
Orange!!!Orange!!!
IxV plot, from OLED based on a new Terbium complex as a function of bias voltage.
Electroluminescence spectra of the Terbium complex.
Picture of a produced OLED.
Conclusions and perspectives: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:Financial Supports:
INEO – Instituto Nacional de Eletrônica INEO – Instituto Nacional de Eletrônica OrgânicaOrgânica