Molecular and solid-state (8-hydroxy-quinoline)aluminum interaction with magnesium: A first-principles study

The interaction between Mg and (8-hydroxyquinoline)aluminum, Alq(3), is investigated via ab initio molecular dynamics based on density-functional theory. We model the Alq(3) thin film both with a single Alq(3) molecule in vacuo (as is usually done in the literature) and with an Alq(3) crystalline structure. Comparing the results from these two models, we show that bulk calculations provide a better description of the chemical processes involved, allowing the Mg atom to react with two neighboring Alq(3) molecules, as was alluded to in a previous publication [S. Meloni, A. Palma, A. Kahn, J. Schwartz, and R. Car, J. Am. Chem. Soc. 125, 7808 (2003)]. Moreover, core-level shift calculations are in good agreement with experimental measurements only when using the solid phase approach. We also propose a different interpretation of the Al(2p) experimental core level presented in a previous work [C. Shen, A. Kahn, and J. Schwartz, J. Appl. Phys. 89, 449 (2001)].