Organic dye-sensitized solar cells containing alkaline iodide-based gel polymer electrolytes: Influence of cation size
Artikel i vetenskaplig tidskrift, 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.

Författare

Ottavia Bettucci

Isituto di Chimica dei Composti Organometallici (ICCOM)

Università degli Studi di Siena

Valeria Saavedra

Chalmers, Kemi och kemiteknik, Kemi och biokemi, Fysikalisk kemi

T M W J Bandara

University of Colombo

Institutionen för fysik

Maurizio Furlani

Chalmers, Fysik, Fasta tillståndets fysik

Maria Abrahamsson

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Bengt-Erik Mellander

Chalmers, Fysik, Subatomär fysik och plasmafysik

Lorenzo Zani

Isituto di Chimica dei Composti Organometallici (ICCOM)

Physical Chemistry Chemical Physics

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

Vol. 20 1276-1285

Ämneskategorier

Fysikalisk kemi

Materialkemi

Annan kemi

DOI

10.1039/c7cp07544h