AVS 46th International Symposium
    Organic Electronic Materials Topical Conference Monday Sessions
       Session OE-MoP

Paper OE-MoP2
Ordered Thin Film and Organic Heterojunction Formation from Luminescent Organic Dyes

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: D.M. Alloway, University of Arizona
Authors: D.M. Alloway, University of Arizona
N.R. Armstrong, University of Arizona
A. Back, Physical Electronics
B. Schilling, VG Micromass
Correspondent: Click to Email
Perylenes, phthalocyanines, certain quinacridones, and related dyes can be vacuum deposited to form ordered monolayers and multilayers. The ordering in these monolayers can be monitored with electron diffraction techniques, and scanning probe microscopies (STM/AFM), but we have recently also found that luminescence spectroscopies can be used to follow the nucleation and growth of the first monolayer, and subsequent multilayer formation. This paper will focus on recent studies of the growth of perylenetetracarboxylicdianhydridebisimide (PTCDI) dyes (both C4 and C5 tails on the bisimide), and substituted quinacridones on both single crystal metal and nonmetal surfaces. Layered growth is seen in all multilayer films, with flat-lying monolayers apparently formed in most cases, and where the structure of the 2nd and subsequent layers is strongly dependent upon the stable bulk structures for these materials. Luminescence spectroscopies indicate the degree of cofacial interaction between these dyes, during monolayer nucleation, and as layer-by-layer growth is achieved. For certain quinacridone dyes the substituent side chains control the approach distance of adjacent molecules, significantly altering the luminescence spectra relative to the parent molecule. In addition, luminescence spectra are useful in characterizing the degree of interaction between two dissimilar dyes, at the organic/organic' interface in a heterojunction assembly, and the degree of luminescence quenching appears to correlated with interface dipole formation as indicated by XPS/UPS studies.