Donor-Acceptor-Donor-based pi-Conjugated Oligomers for Nonlinear Optics and Near-IR Emission

    Authors

    S. Ellinger; K. R. Graham; P. J. Shi; R. T. Farley; T. T. Steckler; R. N. Brookins; P. Taranekar; J. G. Mei; L. A. Padilha; T. R. Ensley; H. H. Hu; S. Webster; D. J. Hagan; E. W. Van Stryland; K. S. Schanze;J. R. Reynolds

    Comments

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    Abbreviated Journal Title

    Chem. Mat.

    Keywords

    near-infrared emission; PLED; two-photon absorption; donor-acceptor; oligomers; controlled HOMO-LUMO gap; EXCITED-STATE ABSORPTION; FIELD-EFFECT TRANSISTORS; FRANCK-CONDON; FACTORS; BAND-GAP; 2-PHOTON ABSORPTION; PHOTOPHYSICAL PROPERTIES; POLYMETHINE DYES; CHARGE-TRANSFER; CROSS-SECTIONS; SINGLE-BEAM; Chemistry, Physical; Materials Science, Multidisciplinary

    Abstract

    A family of multi-heterocycle donor acceptor donor (DAD) telechelic conjugated oligomers designed for two-photon absorption (2PA) and emission in the near-infrared (near-IR) were prepared, and the relationship between their spectral, structural, and electrochemical properties were investigated. These oligomers, based on electron-rich thiophene, phenylene, and 3,4-ethylenedioxythiophene (EDOT) units as donors along with electron-deficient benzothiadiazole or its derivative units as acceptors, have been characterized through linear absorbance and fluorescence measurements, nonlinear absorbance, cyclic voltammetry, and differential pulse voltammetry to demonstrate the evolution of narrow HOMO-LUMO gaps ranging from 1.05 to 1.95 eV, with the oligomers composed of EDOT and benzo[1,2-c,3,4-c']bis[1,2,5]thiadiazole (BBT) exhibiting the narrowest gap. The absorption maxima ranges from 517 to 846 nm and the fluorescence maxima ranges from 651 to 1088 nm for the different oligomers. Z-scan and two-photon fluorescence were used to measure the frequency degenerate 2PA of the different oligomers. The oligomer's 2PA cross sections ranged from 900-3500 GM, with the oligomer containing EDOT donor units and a BBT acceptor unit exhibiting the largest 2PA cross section. The use of these oligomers in red to near-IR emitting polymer light-emitting diodes (PLEDs) was demonstrated by blending the soluble emitting oligomers into a suitable host matrix. Energy transfer from the matrix to the emitting oligomer can be achieved, resulting in PLEDs with pure oligomer emission.

    Journal Title

    Chemistry of Materials

    Volume

    23

    Issue/Number

    17

    Publication Date

    1-1-2011

    Document Type

    Article

    Language

    English

    First Page

    3805

    Last Page

    3817

    WOS Identifier

    WOS:000294647700003

    ISSN

    0897-4756

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