Optical properties of thin films of oligothiophenes deposited by organic molecular beam deposition

The optical properties of thin films of two different quaterthiophenes, uns ubstituted and substituted, deposited on different substrates by organic mo lecular beam deposition are briefly illustrated. The absorption spectra of the samples present both the molecular exciton peak, characteristic of stro ngly interacting molecules and polarized along a preferential direction in the most ordered films, and small bands coming from less interacting or mis aligned molecules; these are mostly responsible for the photoluminescence s pectra. (C) 2001 Elsevier Science B.V. All rights reserved.