Effect of Ionic Liquids with Different Cations in I^-/I₃^-Redox Electrolyte on the Performance of Dye-sensitized Solar Cells

Abstract

The effect of the addition of ionic liquids with four different cations (imidazolium, pyrrolidinium, piperidinium and pyridinium) on the performance of dye-sensitized TiO 2 solar cells based on electrolytes containing a tbutylpyridine (TBP) in 3-methoxypropionitrile (MPN) was studied. A total of 18 ionic liquids with mono-, diand tri-alkyl derivatives were used in the present study, and among them a pyridinium cation with a mono-alkyl group showed better cell efficiency than the others. The best photoelectric conversion efficiency, 7.213%, was obtained using 1-hexylpyridinium iodide with an open-circuit photovoltage (V oc ) = 0.731 V, a short-circuit photocurrent density (J sc ) = 16.175 mA/cm 2 , and a fill factor (ff) = 0.610 under AM1.5 and 100 mW/cm 2 illumination.

Supercapacitors based on graphene nanosheets using different non-aqueous electrolytes

“…This is because the former has stronger van der Waals forces than the later. 69,70 This can explain why the solvated ionic size of [BMIM] + is larger than that of [BPy] + but their electrochemical performances are not obviously different. In addition, the viscosities of ILs increase with an increase of alkyl chain length, 69,70 which is because the increase of alkyl chain length results in stronger van der Waals forces among the ions, inhibiting the mobility of ions.…”

“…69,70 This can explain why the solvated ionic size of [BMIM] + is larger than that of [BPy] + but their electrochemical performances are not obviously different. In addition, the viscosities of ILs increase with an increase of alkyl chain length, 69,70 which is because the increase of alkyl chain length results in stronger van der Waals forces among the ions, inhibiting the mobility of ions. It is well known that conductivity is inversely proportional to viscosity, so the higher viscosity hampers the diffusion of the conducting species in the electrolytes, and then leads to the poor electrochemical properties.…”

A Comparative Study of Piperidinium and Imidazolium Based Ionic Liquids: Thermal, Spectroscopic and Theoretical Studies

“…Cyclic alkyl quaternary ammonium (QA) cations, N-alkyl-Nmethylpiperidinium (PIP 1n ; where 1 indicates CH 3 and n= number of carbon in another alkyl substitution) are class of cations whose room temperature ILs (RTILs) are very promising in the field of electrochemical applications due to their high thermal and electrochemical stabilities. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] Recently, PIP 1n ILs found to be potentially useful for electrochemical applications due to their water immiscibility, high conductivities, thermal stabilities and wide electrochemical windows. For example, 1-butyl-1-mehylpiperidinium bis(trifluoromethylsulfonyl)imide (PIP 14 NTf 2 ; where, NTf 2 -: bis(trifluoromethylsulfonyl)imide anion) improves the stabilization of the chemical composition and structure of the sulphur cathode in Li/S cells during charge-discharge cycles.…”

Ionic Liquid-Based Dye-Sensitized Solar Cells—Insights into Electrolyte and Redox Mediator Design

“…18−20 The unique properties of ILs, such as low volatility, wide electrochemical window, good conductivity, as well as chemical and thermal stability made them indeed promising candidates. 7,21,22 However, the high viscosity and low conductivity of tested ILs led to poor conversion efficiencies. 4,23 But it was possible to improve the conductivity using ionic liquid crystals (ILCs).…”

“…However, one of the main drawbacks of DSSCs is their limited lifetime attributed mainly to the volatility of the electrolyte, which becomes particularly problematic at elevated working temperatures . To circumvent this, iodide-based ionic liquids (ILs) have been tested as electrolytes for DSSCs. − The unique properties of ILs, such as low volatility, wide electrochemical window, good conductivity, as well as chemical and thermal stability made them indeed promising candidates. ,, However, the high viscosity and low conductivity of tested ILs led to poor conversion efficiencies. , But it was possible to improve the conductivity using ionic liquid crystals (ILCs) . Higher photocurrent density and photoelectric conversion efficiency were observed for 1-dodecyl-3-methylimidazolium iodide, which exhibits a smectic A (SmA) phase, compared to IL 1-undecyl-3-methylimidazolium iodide, which is not able to form a mesophase.…”