Rare-earth based OLEDs TG-FTIR thermal stability investigation of tetrakis beta-diketonates complexes

摘要

The improvement of operational lifetime and efficiency of organic light-emitting devices has stimulated many studies focused on the mechanisms responsible for their degradation. Such instabilities can be induced by several factors such as (i) current flow and heating, (ii) chemical reactions, (iii) self-conversion of the charge transporting molecules to cation, anion, and/or radical species. This work aims at investigating the thermal stability of rare-earth based tetrakis beta-diketonates complexes like M[Eu(dbm)₄] (M = Li+, TMPip+, and Morf+) through TG technique coupled with FTIR. Preliminary results show that Li[Eu(dbm)₄]·4H₂O complex presents no degradation in its structure until 300 °C. However, evidences of rapid thermal degradation of the other two compounds have been found at temperatures lower than 100 °C, implying that these complexes could be degraded during the thermal deposition process at relatively high temperatures.