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Novel bipyridinium ionic liquids as liquid electrochromic devices
Noémi Jordão1, Luis Cabrita, Fernando Pina
1REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica (Portugal).
Chemistry (Weinheim an Der Bergstrasse, Germany)
|March 1, 2014
Summary
Novel bipyridinium salts were synthesized and characterized for electrochromic applications. A reversible liquid electrochromic device demonstrated the potential of these new viologen materials in advanced display technologies.
Area of Science:
- Materials Science
- Electrochemistry
- Organic Synthesis
Background:
- Viologens, a class of bipyridinium compounds, are known for their redox activity and potential in electrochromic devices.
- Development of novel ionic liquids and organic salts is crucial for advancing energy storage and display technologies.
- Optimization of synthesis and characterization methods is key to obtaining high-purity materials for specific applications.
Purpose of the Study:
- To synthesize and characterize novel mono- and dialkylbipyridinium salts with various anions, including bis(trifluoromethanesulfonyl)imide [NTf2].
- To investigate the physicochemical properties, including thermal stability, viscosity, and electrochemical behavior, of the synthesized organic salts.
- To demonstrate the proof-of-concept for a reversible liquid electrochromic device utilizing a novel dialkylbipyridinium-NTf2 ionic liquid.
Main Methods:
- Selective alkylation synthetic methodologies were optimized for moderate to high yields and purity.
- Comprehensive characterization using NMR spectroscopy ((1)H, (13)C, (19)F), FTIR, elemental analysis, and differential scanning calorimetry (DSC).
- Rheological studies for viscosity and activation energy determination, and electrochemical studies (CV, DPV, SWV) for redox potential evaluation.
Main Results:
- Successfully synthesized and characterized a range of novel mono- and dialkylbipyridinium salts.
- Determined key properties such as melting points, glass transition temperatures, decomposition temperatures, viscosities, and activation energies.
- Demonstrated a reversible liquid electrochromic device using a promising dialkylbipyridinium-NTf2 ionic liquid with [EMIM][NTf2] as the electrolyte.
Conclusions:
- The developed synthetic routes provide access to high-purity bipyridinium salts suitable for electrochromic applications.
- The characterized physicochemical and electrochemical properties highlight the potential of these novel organic salts as electrochromic materials.
- The proof-of-concept device validates the performance of the dialkylbipyridinium-NTf2 ionic liquid in a functional electrochromic system.
