Dicationic stilbazolium salts: structural, thermal, optical, and ionic conduction properties

Pradip K. Bhowmik* (Corresponding Author), Jung J. Koh, David King, Haesook Han, Benoît Heinrich, Bertrand Donnio, Daniel Zaton, Alfonso Martinez-Felipe

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Two series of new dicationic stilbazolium salts containing tosylate and triflimide counterions, respectively, were synthesized and characterized by spectroscopic techniques and elemental analysis. Despite of their promesogenic structures, none of these salts are mesomorphous, and instead they solely exhibit crystalline polymorphism, as deduced from differential scanning calorimetry, polarizing optical microscopy and variable temperature X-ray measurements. These salts were also found to be highly thermally stable with decomposition temperatures occurring well above 300 °C, and up to 367 °C for the triflimide salts, as determined by thermogravimetric analysis. UV-Vis absorption and photoluminescent properties were examined in both solution and in the solid state. They exhibited higher absolute quantum yields in the powdered state than in solution. The dielectric response was evaluated by impedance spectroscopy, revealing notable values of short-range conductivity in triflimide salts through amorphous regions. Our work demonstrates the potential of these new stilbazolium salts as advanced materials in optoelectronic devices, with performances that can be tailored by molecular design of the spacer’s flexibility and choice of counter anions.
Original languageEnglish
Article number117311
JournalJournal of molecular liquids
Early online date20 Aug 2021
DOIs
Publication statusE-pub ahead of print - 20 Aug 2021

Keywords

  • Dicationic stilbazolium salts
  • Differential scanning calorimetry
  • Polarized optical microscopy
  • Variable temperature X-ray diffraction
  • UV-vis spectroscopy
  • Luminescence
  • Ionic conductivity

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