Jump to main content
Jump to site search


Time-evolved, far-red, circularly polarised luminescent polymer aggregates endowed with sacrificial helical Si–Si bond polymers

Author affiliations

Abstract

An enantiomeric pair of non-charged, helical dialkylpolysilanes (PSi-R and PSi-S) were endowed with circularly polarised luminescence (CPL) at 700 nm and circular dichroism (CD) at 660 nm when non-helical poly{[dioctylfluorene]-alt-[bis(thiophenyl)-benzothiazole]} (PF8DBT) formed a hetero-aggregate with PSi-R and PSi-S in a 1-to-1 ratio as repeating units. The initial ultraweak CPL (gem) and CD (gabs) amplitudes of the as-prepared aggregates were magnified up to −0.019 at 706 nm (induced by PSi-S) and +0.017 at 695 nm (induced by PSi-R) after prolonged ageing at ambient temperature for 24 h. These CPL amplitudes were maintained after the selective photoscissoring of PSi-S and PSi-R at 313 nm for 60 s. A time-dependent growth behaviour in the hetero-aggregate size (initially ≈400 nm; reached ≈2000 nm in one day) was observed and characterised using dynamic light scattering (DLS). To investigate the origin of the time-evolution characteristics, the energy potential, dipole moments and CD/UV-Vis-near-infrared (NIR) spectra were simulated upon altering the dihedral angle sets of several model oligomers of PF8DBT using density functional theory (DFT)/time-dependent DFT (TD-DFT) (B3LYP/6-31G(d,p)). An additional Zerner's Intermediate Neglect of Differential Overlap (ZINDO) calculation qualitatively established that the two hypothetical, chirally dipole–dipole-cancelled, ππ-stacked, slipped dimers cause red shifts in the CD and UV-Vis-NIR spectra, which were associated with an enhanced |gabs|, ≈1 × 10−3 at 715 nm and 0.5 × 10−3 at 660 nm, compared to the corresponding monomeric value (|gabs| ≈ 0.1 × 10−3 at 620 nm) obtained using TD-DFT.

Graphical abstract: Time-evolved, far-red, circularly polarised luminescent polymer aggregates endowed with sacrificial helical Si–Si bond polymers

Back to tab navigation

Supplementary files

Publication details

The article was received on 01 Mar 2017, accepted on 17 Apr 2017 and first published on 21 Apr 2017


Article type: Research Article
DOI: 10.1039/C7QM00096K
Citation: Mater. Chem. Front., 2017, Advance Article
  •   Request permissions

    Time-evolved, far-red, circularly polarised luminescent polymer aggregates endowed with sacrificial helical Si–Si bond polymers

    M. Fujiki and S. Yoshimoto, Mater. Chem. Front., 2017, Advance Article , DOI: 10.1039/C7QM00096K

Search articles by author

Spotlight

Advertisements