SCIENTIFIC HIGHLIGHTS

Homoconjugation in Light-Emitting Poly(phenylene methylene)s: Origin and Pressure-Enhanced Photoluminescence
Sustainable energy conversion & storage systems

Homoconjugation in Light-Emitting Poly(phenylene methylene)s: Origin and Pressure-Enhanced Photoluminescence


Aleksandr Perevedentsev*, Adrián Francisco-López, Xingyuan Shi, Andreas Braendle, Walter R. Caseri, Alejandro R. Goñi, and Mariano Campoy-Quiles

Macromolecules 2020, 53, 17, 7519–7527
Publication DateAugust 26, 2020 
DOI: https://doi.org/10.1021/acs.macromol.0c01153
29 December 2020
The surprising optical properties of the non-π-conjugated polymer poly(phenylene methylene) (PPM) and its derivatives—that is, absorption in the 350–450 nm and photoluminescence (PL) in the 400–600 nm spectral regions—have been attributed to chromophores formed by homoconjugation along the polymer chain. The enabling role of homoconjugation, however, was hitherto ascertained primarily by excluding alternative origins of luminescence.

The present study offers direct evidence for homoconjugation by employing optical and vibrational spectroscopy to investigate the interplay between the microstructure and solid-state optical properties of PPM and its derivative poly(2,4,6-trimethylphenylene methylene). In particular, polarized Raman and PL spectroscopy of melt-drawn fibers reveal a preferentially perpendicular orientation of the phenylene rings relative to the fiber axis and, simultaneously, a preferentially parallel orientation of the transition dipole moment. PL spectroscopy under applied hydrostatic pressure yields a nearly fourfold increase in PL intensity at 8 GPa, together with a surprising absence of excimer emission. These characteristics, being highly atypical of conventional π-conjugated polymers, highlight the different origin of the optical properties of PPMs and unique opportunities for applications.

 

Hits: 322

Also at ICMAB

  • Hydroxypropyl Cellulose Adhesives for Transfer Printing of Carbon Nanotubes and Metallic Nanostructures

    Information
    30 November 2020 637 hit(s) Energy
    Transfer printing is one of the key nanofabrication techniques for the large‐scale manufacturing of complex device architectures. It provides a cost‐effective and high‐throughput route for the integration of independently processed materials into spatially tailored architectures.

INSTITUT DE CIÈNCIA DE MATERIALS DE BARCELONA, Copyright © 2020 ICMAB-CSIC | Privacy Policy | This email address is being protected from spambots. You need JavaScript enabled to view it.