Articolo in rivista, 2018, ENG, 10.1039/C7CP07544H

Organic dye-sensitized solar cells containing alkaline iodide-based gel polymer electrolytes: influence of cation size

Ottavia Bettucci, Valeria Saavedra Becerril, T. M. W. J. Bandara, Maurizio Furlani, Maria Abrahamsson, Bengt-Erik Mellander, Lorenzo Zani

Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro 2, 53100 Siena, Italy Institute of Chemistry of Organometallic Compounds (CNR-ICCOM), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden Department of Physics, Chalmers University of Technology, SE-41296 Gothenburg, Sweden Department of Physical Sciences, Rajarata University of Sri Lanka, Mihintale, Sri Lanka

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 TiO2 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 TiO2 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.

Physical chemistry chemical physics (Online) 20 , pp. 1276–1285

Keywords

dye-sensitized solar cell, gel electrolyte, cation size

CNR authors

Bettucci Ottavia, Zani Lorenzo

CNR institutes

ICCOM – Istituto di chimica dei composti organo metallici

ID: 381286

Year: 2018

Type: Articolo in rivista

Creation: 2017-12-27 11:11:15.000

Last update: 2022-05-31 09:26:31.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:381286

DOI: 10.1039/C7CP07544H

Scopus: 2-s2.0-85040358388