Near-Field Fluorescence Microscopy of Tris-8-hydroxyquinoline Aluminum Films

The dependence of the nanoscale optical properties of Alq3 on film morphology (Alq3=tris-8-hydroxyquinoline aluminum) is still poorly understood, although Alq3 is widely used as the emissive layer in organic LEDs. Here near-field scanning optical microscopy (NSOM) is used to probe the local optical and morphological properties of Alq3 films. It is shown that features as small as 10–100 nm can be observed, a resolution not obtained with previously used techniques. Differences in the quality of vacuum-deposited, spin-cast, and drop-cast films are investigated using this technique.