Effects of thermal annealing on the photophysical properties of bisfluorene-cored dendrimer films

J. C. Ribierre, A. Ruseckas, O. P.M. Gaudin, I. D.W. Samuel, H. Barcena, S. V. Staton, P. L. Burn

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)

    Abstract

    Annealing is widely used in the processing of organic semiconductors, and can modify their film morphology and photophysical properties. A study of the effect of annealing on films made from a blue emitting bisfluorene-cored dendrimer is reported. Annealing causes a 15 nm blue-shift in the photoluminescence (PL) spectrum and an 11 nm blue-shift in the amplified spontaneous emission (ASE) spectrum. It causes the PL efficiency to decrease only slightly from 0.92 to 0.83. The radiative decay rate of 1.3 × 109 s-1, the ASE threshold of 1.5 × 1018 cm-3 and the singlet-singlet exciton annihilation rate of 5.5 × 10-10 cm3 s-1 are unaffected by annealing. The results indicate a scope for colour adjustment of dendrimer light-emitting diodes and lasers without affecting their efficiencies. Investigation by spectroscopic ellipsometry shows that on annealing, the films become anisotropic, with larger values of the refractive index and extinction coefficient observed for light polarised in the plane of the film than the corresponding out-of-plane values in the absorption region of the bisfluorene core. This anisotropy indicates a preferential in-plane orientation of bisfluorene cores upon annealing.

    Original languageEnglish
    Pages (from-to)803-808
    Number of pages6
    JournalOrganic Electronics
    Volume10
    Issue number5
    DOIs
    Publication statusPublished - Aug 2009

    All Science Journal Classification (ASJC) codes

    • Electronic, Optical and Magnetic Materials
    • Biomaterials
    • Chemistry(all)
    • Condensed Matter Physics
    • Materials Chemistry
    • Electrical and Electronic Engineering

    Fingerprint Dive into the research topics of 'Effects of thermal annealing on the photophysical properties of bisfluorene-cored dendrimer films'. Together they form a unique fingerprint.

    Cite this