Growth and characterization of OLED with samarium complex as emitting and electron transporting layer

In this work, the growth and the characterization of new orange emitting triple-layer electroluminescent organic devices using vacuum deposited trivalent samarium complex [Sm(TTA)(3)(TPPO)(2)] as emission layer is described. The electroluminescence (EL) spectra of the devices show narrow bands arising from the (5)G(5/2) --> 6H(integral) transitions (J = 5/2, 7/2 and 9/2) of the Sm3+ ion with the hypersensitive (5)G(5/2) --> 6H(integral) transitions as the prominent group. The hole transporting layer (HTL) was obtained using a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline-6-carboxyaldehyde-1,1'-diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq(3)) is used as electron transport layer (ETL). Moreover, in order to use the Sm complex, two different kinds of OLEDs were prepared: the first one with a typical three layers architecture, MTCD/[Sm(TTA)(3)(TPPO)(2)]/ Alq(3), while the second one was a bi-layer device with an MTCD/[Sm(TTA)(3)(TPPO)(2)] design without the Alq3 ETL layer. In the last case, the EL emission was also observed, which indicates that the [Sm(TTA)(3)(TPPO)(2)] complex may be used as an electron transporting layer also. (C) 2002 Elsevier Science B.V. All rights reserved.