Unique luminescent properties of rare earth ions in inorganic and organic matrices have been the subject of many studies for many years

including both photoluminescence and electroluminescence. The Er

3+

ion has a sharp luminescence centered at 1530nm due to an intra-4f shell transition between the first excited state (

4

I

13/2

) and the ground state (

4

I

15/2

). Considering the potential use of trivalent erbium complexes as IR emitting materials for optical quartz fiber communication and laser application

we concentrated in organic electroluminescence (EL) from Er

3+

in IR range. Except for notable advantages of current excitation over photo excitation

probability of realizing electric pump laser from Er

3+

which is a usual emitting center in inorganic laser crystals and glasses

is another attractive purpose of this study. Er(DBM)

3

bath and several kinds of other Er-complexes were synthesized according to traditional method in our lab. Bilayer and trilayer EL devices based on Er(DBM)

3

bath were fabricated. Two intense bands at 1530nm and 977nm originated from trivalent Er

3+

ion were observed under a low DC voltage for the first time. Individual organic films and alloy cathode of EL devices were deposited onto indium tin oxide glass substrate successively by thermal evaporation in a vacuum chamber at 5×10

-4

Pa. The made up devices were encapsulated in dried nitrogen. IR(700~2000nm) and visible (400~750nm) spectra were measured by a Biorad PL-9000FT spectrometer and a Hitach-4000 fluorescence spectrophotometer at room temperature

respectively. From ITO/TPD(30nm)/Er(DBM)

3

bath doped TPD(30nm) (about 1:1)/Er(DBM)

3

bath(60nm)/Mg:Ag(150nm) (device I)

intense emitting band locating at 1530 nm corresponding to

4

I

13/2

→

4

I

15/2

transitions of Er

3+

was observed. Almost pure emissions from Er

3+

were obtained including a weaker peak at 977nm

which was originated from

4

I

11/2

→

4

I

15/2

transition. IR emissions were accompanied by visible emitting for both bilayer and trilayer devices. Emitting spectra of the two types of devices were quite different. This indicates that radiative decay of the lowest excited state of ligand occurred through not only f-f transition of Er

3+

ion but also other ways.