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: ales_p18@yahoo.com.br

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