Self-Assembled Multinuclear Complexes for Cobalt(II/III) Mediated Sensitized Solar Cells

Edoardo Marchini,Roberto Argazzi,Rita Boaretto,Vito Cristino,Alessandro Niorettini,Stefano Caramori,Carlo Alberto Bignozzi

doi:10.3390/app11062769

Edoardo Marchini, Roberto Argazzi + Show 5 more

Open Access

https://doi.org/10.3390/app11062769

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Journal: Applied sciences	Publication Date: Mar 19, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of Ferrara

Abstract

In this work, we designed a tetranuclear self-assembled dye 4 (2Z907-Ag+-(Ru(TMAM))) exploiting a combination of the antenna effect and positively-charged groups designed to repel the oxidized form of cationic cobalt redox mediators, in order to reduce recombination and increase the efficiency of dye sensitized solar cells (DSSCs). Charge transfer and excited dynamics were probed by photoelectrochemical and photophysical measurements. The sensitized cell performance, recorded with a [Co(bpy)3]3+/2+ redox mediator and PEDOT counter electrode, showed an improvement when passing from Z907 to the multinuclear systems. The enhancement of the efficiency compared to Z907 resulted mainly from a superior steric and electrostatic shielding determined by the simultaneous presence of long alkyl chains and quaternary ammonia ion units in the architecture of 4.

Highlights

Titania based dye sensitized solar cells (DSSCs), developed starting in the early 90s by Grätzel and O’Regan [1], represent a regenerative photoelectrochemical device type characterized by unique properties like transparency, low production cost, capability to harvest the diffuse light [2], and wide choice of color palette, which facilitate its building integration in both indoor and outdoor conditions [3,4]
The functioning of DSSCs is based on photoinduced charge transfer from a molecular sensitizer adsorbed on a porous semiconductor followed by its regeneration from a hole transporting phase, which commonly consists of a redox couple dissolved in an organic electrolyte
A multinuclear compound 4 comprising a Ru(TMAM)2 (CN2 )]4+ (TMAM = (bis-4,40 bis(trimethylaminomethyl)2,20 bipyridine) and 2 Z907 units was obtained by bridging the ancillary ligands with Ag+ ions

Summary

Introduction

Titania based dye sensitized solar cells (DSSCs), developed starting in the early 90s by Grätzel and O’Regan [1], represent a regenerative photoelectrochemical device type characterized by unique properties like transparency, low production cost, capability to harvest the diffuse light [2], and wide choice of color palette, which facilitate its building integration in both indoor and outdoor conditions [3,4]. The functioning of DSSCs is based on photoinduced charge transfer from a molecular sensitizer adsorbed on a porous semiconductor followed by its regeneration from a hole transporting phase, which commonly consists of a redox couple dissolved in an organic electrolyte. Other approaches to suppress recombination caused by fast redox couples involve either the co-adsorption of siloxanes [9] to saturate the surface sites uncovered by the dye sensitizers and exposed to the electrolyte, or the formation of insulating thin metal oxide layers including alumina and magnesia [10].

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