ORALS

SESSION: ElectrochemistryWedAM-R2	Amatore International Symposium on Electrochemistry for Sustainable Development
Wed Nov, 7 2018 / Room: Copacabana B (150/1st)
Session Chairs: Meng Tao; Session Monitor: TBA

11:45: [ElectrochemistryWedAM02]
Performance of Lyotropic Liquid Crystal-based Photoelectrochemical Capacitors for Solar-to-Electrical Energy Conversion
Jonathan Halls¹ ; Haydn Ward¹ ; Amal A. Althali¹ ; Laetitia Testut¹ ; David Kocsis¹ ; Huda S. Alhassan¹ ; S.m. Kelly¹ ; Nathan Lawrence¹ ; Jay Deep Wadhawan² ; ¹The University of Hull, Hull, United Kingdom; ²The University of Hull, Kingston-upon-Hull, United Kingdom;
Paper Id: 410 [Abstract]

Regenerative photoelectrochemical capacitors adapted from an experimental system previously reported (J. E. Halls, J. D. Wadhawan, Energy Environ. Sci., 2012, 5, 6541) and based on the doping of a lamellar lyotropic liquid crystal with visible light sensitizer tris(2,2'-bipyridyl)ruthenium(II), N-methylphenothiazine, zinc(II) ions and potassium chloride (as electrolyte) are examined in this work. The two dye species, by virtue of similarity in redox potentials and difference in size and lipophilicity, allow for electron transfer cascades to occur under illumination, which can be harnessed in a power-generating device through the use of a sacrificial counter electrode. In operation as a solar cell, a maximum light-to-electrical power conversion efficiency is reported as being 5.0% under green light (530 nm centreband, 30 nm bandwidth, 2.2 mW cm-2 intensity), which extrapolates to the opportunistic value of 1% under one Sun conditions. The electrical characteristics of the devices under illumination afford specific capacitances of ca. 2 F g-1 and have fill factors ~20% which are close to the 25% expected for a perfect photogalvanic cell. The time constants of the reported devices (~1 s) are consistent with the notion of electroporation of the surfactant lamellæ. The advantages of these mid-ranging photoelectrochemical capacitors are suggested as being their low cost and versatility afforded by their flexible liquid framework that is able to realign itself under conditions of open circuit.

References:
J. E. Halls, J. D. Wadhawan, Energy Environ. Sci., 2012, 5, 6541