Experimental study of a chemical reaction between LiF and Al

The interaction between LiF and Al has been studied by x-ray photoemission spectroscopy and high-resolution electron energy loss spectroscopy (HREELS). At room temperature, reaction between LiF and Al already occurred in the presence of Alq(3), as revealed by the 0.25 eV shift of the Li 1s peak relative to the F 1s peak. Upon heating the LiF-coated Al substrate above 70 degreesC, reaction between LiF and Al also occurred in the absence of Alq(3), suggested by the emergence of a peak 0.85 eV below the original Li 1s peak. The relatively large shift of 0.85 eV indicated that the emergent Li state possessed a metallic character. The reaction between LiF and Al upon heating was also corroborated by HREELS measurements. Heating of the Al/LiF/polymer device enhanced its electroluminescence, and may be associated with free Li atoms. (C) 2003 American Institute of Physics.