Bio-based quaternary ammonium salt as an electrolyte for dye-sensitised solar cells

Abstract

Conventional ionic liquids have been observed in various applications due to their unique properties and significant potential. This preliminary study investigated the synthesis of a bio-based quaternary ammonium salt (QAS) ionic liquid crystals (ILC) using lauric acid as an alternative and renewable feedstock. The organic ILC was synthesised through a non-catalytic two-step facile reaction involving amidation and solventless quaternisation. Numerous spectroscopic techniques confirmed the chemical structure of each compound, in which the ionic conductivities of the QAS were approximately 10−6 S cm−1 at 0 °C and 10−5 S cm−1 at 60 °C. This outcome indicated a stable relationship between ionic conductivity and temperature. Furthermore, this novel compound displayed solid-solid transitions at 48 °C and 78 °C before reaching its melting point at 109 °C. Solid-solid transitions at these temperatures also suggested the ILC behaviour. Consequently, these preliminary findings demonstrated that the bio-based QAS was a promising electrolyte for dye-sensitised solar cells, achieving a power conversion efficiency of 1.0 %.