Organic dye-sensitized solar cells containing alkaline iodide-based gel polymer electrolytes: Influence of cation size
Journal article, 2018

The electrolyte used in dye-sensitized solar cells (DSSCs) plays a key role in the process of current generation, and hence the analysis of charge-transfer mechanisms both in its bulk and at its interfaces with other materials is of fundamental importance. Because of solvent confinement, gel polymer electrolytes are more practical and convenient to use with respect to liquid electrolytes, but in-depth studies are still necessary to optimize their performances. In this work, gel polymer electrolytes of general formulation polyacrylonitrile (PAN)/ethylene carbonate (EC)/propylene carbonate (PC)/MI, where M + is a cation in the alkaline series Li-Cs, were prepared and used in DSSCs. Their ionic conductivities were determined by impedance analysis, and their temperature dependence showed Arrhenius behavior within the experimental window. FT-IR studies of the electrolytes confirmed the prevalence of EC coordination around the cations. Photo-anodes were prepared by adsorbing organic sensitizer D35 on nanocrystalline TiO 2 thin films, and employed to build DSSCs with the gel electrolytes. Nanosecond transient spectroscopy results indicated a slightly faster dye regeneration process in the presence of large cations (Cs + , Rb + ). Moreover, a negative shift of TiO 2 flat-band potential with the decreasing charge density of the cations (increasing size) was observed through Mott-Schottky analysis. In general, results indicate that cell efficiencies are mostly governed by photocurrent values, in turn depending on the conductivity increase with cation size. Accordingly, the best result was obtained with the Cs + -containing cell, although in this case a slight reduction of photovoltage compared to Rb + was observed.

Author

Ottavia Bettucci

Institute of Chemistry of Organometallic Compounds (ICCOM)

University of Siena

Valeria Saavedra

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry, Physical Chemistry

T M W J Bandara

University of Gothenburg

University of Colombo

Maurizio Furlani

Chalmers, Physics, Solid State Physics

Maria Abrahamsson

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Bengt-Erik Mellander

Chalmers, Physics, Subatomic and Plasma Physics

Lorenzo Zani

Institute of Chemistry of Organometallic Compounds (ICCOM)

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 20 2 1276-1285

Subject Categories

Physical Chemistry

Materials Chemistry

Other Chemistry Topics

DOI

10.1039/c7cp07544h

More information

Latest update

9/2/2019 6