English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Polyfluorenes (PFs) represent a unique class of poly para-phenylene basedblue-emitting polymers with intriguing structure-property relationships. Slightvariations in the choice of functionalizing side chains result in dramaticdifferences in the inter- and intra-chain structures in PFs. We presentphotoluminescence (PL) and Raman scattering studies of bulk samples and thinfilms of dioctyl-substituted PF (PF8) under hydrostatic pressure. The bulksample was further thermally annealed at 1.9 GPa. The PL vibronics of the as-issample red-shift at an average rate of 26 meV/GPa. The thermally annealedsample is characterized by at least two phase transitions at 1.1 GPa and 4.2GPa, each of which has a different pressure coefficient for PL vibronics. TheHuang-Rhys factor, a measure of the electron-phonon interaction, is found toincrease with increasing pressures signaling a higher geometric relaxation ofthe electronic states. The Raman peaks harden with increasing pressures; theintra-ring C-C stretch frequency at 1600 cm$^{-1}$ has a pressure coefficientof 7.2 cm$^{-1}$/GPa and exhibits asymmetric line shapes at higher pressures,characteristic of a strong electron-phonon interaction. The optical propertiesof PF8 under high pressure are further contrasted with those of a branched sidechain substituted PF.

Tuning intermolecular interactions in di-octyl substituted polyfluorene via hydrostatic pressure