Time-resolved photoluminescence characterisation of thin PTCDA films on Si(100)

3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA) thin films on Si(100) substrate are investigated by time-resolved photoluminescence (PL). A sub-b and structure together with a bi-exponential decay of the PL spectra have b een observed which are attributed to excimer and monomer recombination proc esses. A comparison with single PTCDA crystals shows that the excimer trans ition is related to the crystallinity of the PTCDA films. The dependence of the photoluminescence intensity and decay times on the film thickness and on the substrate temperature give further information about the crystallini ty of PTCDA films. (C) 2001 Elsevier Science B.V. All rights reserved.