Langmuir-Blodgett (LB) films of Eu(dpm)(3) (dpm = 2,2,6,6-tetramethyl-3,5-heptanedionate) and Gd(dpm)(3) coexisting with arachidic acid (AA) (complexes: AA = 1:2, in molar ratio) with different molar percentages were prepared. Luminescence enhancement of Gd(dpm)(3) on Eu(dpm)(3) in the mixed films was studied in detail. The mixed monolayers of Eu(dpm)(3)/Gd(dpm)(3)/AA with different molar proportions at air-water interface were studied by pi-A isotherms behaviors. The mixed LB films were characterized by means of low angle X-ray diffraction (LAXRD), UV-visible absorption spectra and photo-induced emission spectra. The possible structure of its resulting LB film was proposed. The results of UV-visible absorption spectra indicated that the complexes of rare earth-beta-diketonate were homogeneously transferred onto the substrates layer-by-layer. The results of luminescence spectra also indicated that Gd(dpm)(3) and Y(dpm)(3) had a luminescence enhancement effect on Eu(dpm)(3) in the mixed LB films, while Gd(dpm)(3) had a stronger luminescence enhancement effect. (C) 2004 Published by Elsevier B.V.