Electrochemical characterization of Prussian blue type nickel hexacyanoferrate redox mediator for potential application as charge relay in dye-sensitized solar cellsReport as inadecuate




Electrochemical characterization of Prussian blue type nickel hexacyanoferrate redox mediator for potential application as charge relay in dye-sensitized solar cells - Download this document for free, or read online. Document in PDF available to download.

Journal of Solid State Electrochemistry

, Volume 15, Issue 11–12, pp 2545–2552

First Online: 09 August 2011Received: 04 May 2011Revised: 13 July 2011Accepted: 14 July 2011

Abstract

A polynuclear electronically-ionically redox conducting mixed-valent inorganic material such as nickelII hexacyanoferrateII,III, NiHCF, was considered for potential application as a redox mediator charge relay in dye-sensitized solar cell DSSC. The NiHCF redox reactions were found fast and reversible not only when the system was studied as thin film exposed to an aqueous supporting electrolyte but also as bulk material pasted powder in solid state, i.e., in the absence of contact with external liquid electrolyte phase. Usefulness of NiHCF material was diagnosed using conventional electroanalytical approaches, solid-state voltammetric methodology, as well as the dynamic electrochemical impedance spectroscopy technique that permitted monitoring of impedance spectra under potentiodynamic conditions. The material was utilized in a mixed-valent state, i.e., as a mixture of K4NiFeCN6 and K3NiFeCN6 in which ironII and ironIII sites were at the 1:1 ratio. Under such conditions, dynamics of electron-hopping between mixed-valent iron sites was maximized. Our DSSC utilized cis–dithiocyanoatobis4,4′-dicarboxylic acid-2,2′-bipyridine rutheniumII dye N3 adsorbed onto TiO2 semiconductor and NiHCF as redox mediator. Although performance of our DSSC was not optimized in terms of the NiHCF film thickness and morphology, as well as lower photocurrents in comparison to those characteristic of the iodine-iodide based DSSC were obtained, our system yielded readily fairly high open-circuit photovoltages on the level of 800 mV. An important issue was that the formal potential of NiHCF was more positive relative to the potential of the iodide-triiodide couple while being still more negative than that equivalent to the ground state of the N3 dye. Thus, NiHCF mediator was able to regenerate the dye.

KeywordsMetal hexacyanoferrate Sol–gel processed deposits Solid-state voltammetry charge propagation Charge relay Solar cell  Download fulltext PDF



Author: Iwona A. Rutkowska - Adam Andrearczyk - Sylwia Zoladek - Monika Goral - Kazimierz Darowicki - Pawel J. Kulesza

Source: https://link.springer.com/







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