Optical properties of oligothiophene hetero-structures grown by organic molecular beam deposition

The photophysical properties of thin multilayer hetero-structures of quater - (4T) and sexi-thiophene (6T) grown by organic molecular beam deposition ( OMBD) on fused silica are investigated. The analysis of their optical spect ra allows the determination of the orientation of the different molecules. Moreover, evidence of energy transfer from excited states of 4T to excited states of 6T is given. Comparison between photophysical and structural prop erties of these hetero-structures suggests that the mutual orientation of 4 T and 6T molecules influence the efficiency of energy transfer from donor ( 4T) to acceptor (6T), in agreement with Forster theory. (C) 2001 Elsevier S cience B.V. All rights reserved.