Solvent‐Free Ionic Liquid Electrolytes for Mesoscopic Dye‐Sensitized Solar Cells

Abstract

Ionic liquids have been identified as a new class of solvent that offers opportunities to move away from the traditional solvents. The physical‐chemical properties of ionic liquids can be tuned and controlled by tailoring their structures. The typical properties of ionic liquids, such as non‐volatility, electrochemical stability and high conductivity, render them attractive as electrolytes for dye‐sensitized solar cells. However, the high viscosity of ionic liquids leads to mass transport limitations on the photocurrents in the solar cells at full sunlight intensity, but the contribution of a Grotthous‐type exchange mechanism in these viscous electrolytes helps to alleviate these diffusion problems. This article discusses recent developments in the field of high‐performance dye‐sensitized solar cells with ionic liquid‐based electrolytes and their characterization by electrochemical impedance analysis.

Rational screening low-cost counter electrodes for dye-sensitized solar cells

“…They show the current density (J) as a function of voltage (U) at 20°C for the oxidation/reduction of triiodide to iodide. The slope of a tangent to the a-Fe 2 O 3 curve is higher than that of Pt, indicating that a-Fe 2 O 3 shows a larger exchange current density (J 0 ), which is also in good agreement with the EIS values in terms of the following equation (3) 12,33 .…”

Conduction Through Viscoelastic Phase in a Redox‐Active Ionic Liquid at Reduced Temperatures

“…The enhanced performance at high concentrations ([I 2 ] a 3.9 M) is hard to reach for PMII electrolytes in dye sensitized solar cells which are optimally doped at [I 2 ] a 0.5 M. [23] High I 2 concentrations cause increased absorbance of the sunlight necessitating a compromise between transparency and conductivity in the PMII electrolyte. This compromise may be circumvented by reducing the spacer thickness between photo anode and counter electrode in order to reduce the light absorption.…”

Water-induced correlation between single ions imaged at the solid–liquid interface

“…This assumption becomes problematic at the nanoscale where most solids exhibit some structure with localized charges and a welldefined hydration landscape that can determine the position and organization of single ions at the interface. Such a complexity is key to many processes such as the folding and function of biomolecules 11 , the accumulation and transfer of charges at the surface of extremophiles 12,13 or at the electrodes of solar cells 14 , electro-friction 15 , the nucleation of nanoparticles on surfaces 16 , or the preferential adsorption of a particular type of ion onto minerals 17 . Even at the macroscopic level, intense research is currently dedicated to the synthesis of colloid particles exhibiting non-homogeneous charge distributions at their surface for better controlling the stability or ordering of colloidal solutions 18 .…”