The 4th African Conference on Fundamental and Applied Physics (ACP2025)

Electrochemical impedance spectroscopy (EIS) study of the interfacial parameters of [the ITO-Pt electrode] // [electrolytes (KI:EG:I2)], prepared with different KI:EG molar ratios and variable diiodine concentration.

16 Sept 2025, 16:50

5m

Contributed Poster Presentation Physics Research Poster Room

Speaker

Mr David Amenou (Université de Lomé)

Description

〖 〖Akotchayé Amenou〗^(1,2),Komi Apélété Amou〗^(1,2 ),〖Komlan Segbéya Gadedjisso〗^(2,3) 〖 Essowè Mouzou〗^(1,2) 〖,Mazabalo Baneto〗^(1,2),〖Ayayi Claude Ahyi〗^(4,5)
1_(Solar Energy Laboratory,Department of Physics,Faculty of Science,University of Lomé,01BP 1515,Lomé,Togo) ) 2_(Regional Center of Excellence for the Mastery of Electricity (CERME),University of Lome,01BP1515,Lome,Togo) ) 3_(Laboratory of Physics of Materials and Semiconductor Components,Department of Physics) 4_(Department of Physics,Auburn University,Auburn,AL 36849,United States ) 5_(National Coalition of Independent Researchers,United States )
Abstract: In dye-sensitized solar cells (DSSCs), charge transport performance strongly depends on the properties of the interfaces between the electrolytes and the electrodes. The resistances and capacitances associated with these interfaces play a key role in the dynamics of charge transfer and ion diffusion. This study analyzes by electrochemical impedance spectroscopy (EIS), the parameters related to the interface [ITO-Pt electrode]//[electrolyte (KI:EG:I2)], in order to evaluate the combined influence of the KI:EG molar ratio (1:5; 1:7; 1:9; 1:11) and the iodine concentration (0.001M; 0.005M; 0.01M) on the electrolyte performance [KI:EG:I2]. Twelve electrolyte formulations (KI:EG:I2), were prepared and characterized by EIS.The results reveal significant correlations between electrolyte composition and its electrochemical properties. The 1:7 molar ratio at 0.001M of I2, exhibits lower average charge transfer resistances (Rct1= 5.204 ; Rct2 = 45.99) and diffusion resistance (Rd=242.6 ), indicating optimal ionic conductivity due to the efficient KI:EG:I2 coordination network. However, its pseudo-capacitive capacitances: (CPE1=9.72F; CPE2= 304F) are lower than those of the ratios: 1:9 at 0.001M: (CPE1= 20.85F ; CPE2= 639F) 1:11 at 0.001M: ( CPE1 = 23.36F ; CPE2 = 128F); 1:7 at 0.005M: ( CPE1 = 17.77F ; CPE2 =176F) and 1:11 at 0.005M: ( CPE1=23.14F ; CPE2 =616F ), suggesting low interfacial stability. The results also show that at low concentration (0.001M); The constant phase element (CPE) increases linearly in the order: CPE (1:5) < CPE (1:7) < CPE (1:9) < CPE (1:11), indicating better ionic interaction in the electrolyte. However, at higher concentrations (0.005M and 0.01M), the CPE no longer follows this linear trend. This suggests saturation of the active sites and non-swimmable diffusion resistances.
Keywords: Electrolytes; Potassium iodide; Ethylene glycol; Diiodine, Electrochemical impedance spectroscopy (EIS); Deep eutectic solvents, Resistance, constant phase capacity

Presentation materials

RESUME.pdf