Near-Field Scanning Optical Microscopy of Temperature- and Thickness-Dependent Morphology and Fluorescence in Alq3 Films

• Published in: Chemistry of materials 2001-04, Vol.13 (4), p.1258-1265
• Main Authors: Credo, Grace M, Winn, Darby L, Buratto, Steven K
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Polymers; organic compounds; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm000672o

We use near-field scanning optical microscopy (NSOM) to probe the local optical and morphological properties in annealed, vacuum-deposited Alq3 films (10−480-nm thick) with 10−100-nm resolution. We use concurrent shear force microscopy (an analogue to atomic force microscopy, AFM) to correlate the morphology of different regions to intensity variations in our fluorescence images as well as variations in the localized fluorescence spectra. We have observed nanoscale effects of annealing temperature on film morphology and fluorescence emission. Our studies show that Alq3 films annealed below the glass transition temperature of Alq3 (T < T g = 172 °C) were very similar to unannealed films, except in very thin films (