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 5G5/2→6HJ transitions (J=5/2, 7/2 and 9/2) of the Sm3+ ion with the hypersensitive 5G5/2→6HJ 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) (Alq3) 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]/Alq3, 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.