Strong interfacial dipole formation with thermal evaporation of lithium cobalt oxide for efficient electron injections

摘要: We investigated the electronic structures at interface of Al/lithium cobalt oxide (LiCoO2)/tris(8-hydoxyquinoline) aluminum (Alq3) to elucidate origin electron injection enhancement with insertion LiCoO2 layer in organic light-emitting devices using situ photoelectron spectroscopy experiments. discovered that was decomposed into lithium (Li2O) by thermal evaporation, and only Li2O deposited on desired substrate. forms a strong interfacial dipole, which reduces surface potential Alq3 due its extremely low work function. As result, barrier dramatically decreased layer. Furthermore, there is no chemical interaction Al/Li2O/Alq3; hence, this would contribute extend device lifetime.