Band-Gap Energies of Choline Chloride and Triphenylmethylphosphoniumbromide-Based Systems
Academic Article
Publication Date:
2020
Abstract:
UV–VIS spectroscopy analysis of six mixtures containing choline chloride or
triphenylmethylphosphonium bromide as the hydrogen bond acceptor (HBA) and dierent hydrogen
bond donors (HBDs, nickel sulphate, imidazole, d-glucose, ethylene glycol, and glycerol) allowed to
determine the indirect and direct band-gap energies through the Tauc plot method. Band-gap energies
were compared to those relative to known choline chloride-containing deep band-gap systems.
The measurements reported here confirmed the tendency of alcohols or Lewis acids to increment
band-gap energy when employed as HBDs. Indirect band-gap energy of 3.74 eV was obtained in
the case of the triphenylmethylphosphonium bromide/ethylene glycol system, which represents the
smallest transition energy ever reported to date for such kind of systems
triphenylmethylphosphonium bromide as the hydrogen bond acceptor (HBA) and dierent hydrogen
bond donors (HBDs, nickel sulphate, imidazole, d-glucose, ethylene glycol, and glycerol) allowed to
determine the indirect and direct band-gap energies through the Tauc plot method. Band-gap energies
were compared to those relative to known choline chloride-containing deep band-gap systems.
The measurements reported here confirmed the tendency of alcohols or Lewis acids to increment
band-gap energy when employed as HBDs. Indirect band-gap energy of 3.74 eV was obtained in
the case of the triphenylmethylphosphonium bromide/ethylene glycol system, which represents the
smallest transition energy ever reported to date for such kind of systems
CRIS type:
1.1 Articolo in rivista
Keywords:
deep eutectic solvents; deep band-gap systems; UV–VIS; Tauc plot; molten systems
List of contributors:
Mannu, Alberto; Enrica Di Pietro, Maria; Mele, Andrea
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