The Langmuir-Blodgett (LB) technique was used for studying enhanced lumines-cence of Eu (TTA)3 Phen (acceptor) by La (TTA)3 Phen (donor). LB films studied here are:(1) [0. 5% Eu (TTA)3 Phen + 99. 5% La (TTA)3 Phen]: AA = 1: 1; (2) [0. 5%Eu(TTA)3 Phen+99. 5%AA]: AA= 1: 1; (3) La(TTA)3 Phen: AA= 1: 1. These filmscould form stable monolayers at air/water surface. The fluorescence intensity of LB 1 was 65times stronger than that of LB2. This signifies that the luminescence intensity ofEu(TTA)3 Phen could be enhanced by La (TTA)3 Phen clearly. Low angle X-ray diffrac-tog ram of LB1 showed that the film has a period layered structure. To study the intermolec-ular energy transfer, different structures of the multilayer were designed by combining LB2(layer of acceptor) with LB3(layer of donor). The results indicated that the intermolecularenergy transfer occurred in a short-range (<3 nm) and at the position of head-head in Y-typemodel. The influence of the interface on the energy transfer was prominent. The process ofenergy transfer was carried out via the triplet state of TTA.
