The interfacial interactions resulted from various Cs-derivatives, including cesium carbonate (Cs2CO3), cesium fluoride (CsF), and cesium nitrite (CsNO3), with tris-(8-hydroxyquinoline)-aluminum (Alq(3)) in organic light emitting diodes (OLEDs) were investigated via photoemission spectroscopy and current-voltage characteristics. The n-type doping effect caused by Cs2CO3 in Alq(3) is most efficient among the three compounds. Based on the results of current injection efficiency, the performance of OLEDs with CsF in cathode structures is similar to that with Cs2CO3, which can function well with both Al and Ag in cathodes. The interfacial reactions in cathodes incorporated with CsNO3 are different than that with two other Cs-derivatives, leading to the reaction between Al and CsNO3 which could lower the electron injection barrier. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3354982] All rights reserved.