Effect of Iodide-Based Organic Salts and Ionic Liquid Additives in Dye-Sensitized Solar Cell Performance

Abstract

The use of ionic liquid and organic salts as additives for electrolyte systems in dye-sensitized solar cells have been widely described in recent years. The tunability of their physical-chemical properties according to the cation–anion selection contributes toward their high efficiencies. For this purpose, several iodide-based organic salts including imidazolium, picolinium, guanidinium and alkylammonium cations were tested using acetonitrile/valeronitrile electrolytes and their photovoltaic parameters were compared. A best efficiency of 4.48% (4.15% for the reference) was found for 1-ethyl-2,3-dimethylimidazolium iodide ([C2DMIM]I) containing electrolyte, reaffirming the effectiveness of these additives. 4-tertbutylpyridine was included into the formulation to further improve the performance while determining which iodide salts demonstrate the highest synergy with this additive. [C2DMIM]I once again proved to be the superior additive, achieving an efficiency of 6.48% (6% for the reference). Electrochemical impedance spectroscopy was employed to elucidate the effects of the various additives, demonstrating the relevance of the counter electrode resistance on device performance. Finally, several computational descriptors for the cationic structures were calculated and correlated with the photovoltaic and resistance parameters, showing that properties related to polarity, namely relative positive charge, molecular polarizability and partition coefficient are in good agreement with the counter-electrode resistance.

Counterion effects on the mesomorphic and electrochemical properties of guanidinium salts

“…26 ILs based on guanidinium cations and trifluorosulfonimide anions have been previously investigated regarding their electrochemical properties [27][28][29] as additives in electrolytes for DSSCs, 30 as well as guanidinium-functionalized anion exchange polymer electrolytes. 31 In addition, the electrochemical properties of guanidines and the respective guanidinium salts were studied with respect to their applications as redox active ligands of metal complexes. [32][33][34][35] Moreover, aminocyclopropenium ions have been introduced as deltic guanidinium ions, i.e.…”

Computational, Investigational Explorations on Structural, Electro-Optic Behavior of Pelargonidin Organic Colorant for TiO2 Based DSSCs

“…Semiconductor, colorant sensitizer, electrolyte and electrode are all part of it. DSSC efficiency is primarily determined by its components, design, and fabrication processes [8][9][10]. Because of its obtainability, superior stability, non-toxicity and costeffectiveness, TiO 2 is a perfect choice for DSSC owing to its size, shape and dimensionality which all have a strong influence on the efficiency of DSSCs.…”