Issue 5, 2022

Solar energy conversion using first row d-block metal coordination compound sensitizers and redox mediators

Abstract

The use of renewable energy is essential for the future of the Earth, and solar photons are the ultimate source of energy to satisfy the ever-increasing global energy demands. Photoconversion using dye-sensitized solar cells (DSCs) is becoming an established technology to contribute to the sustainable energy market, and among state-of-the art DSCs are those which rely on ruthenium(II) sensitizers and the triiodide/iodide (I3/I) redox mediator. Ruthenium is a critical raw material, and in this review, we focus on the use of coordination complexes of the more abundant first row d-block metals, in particular copper, iron and zinc, as dyes in DSCs. A major challenge in these DSCs is an enhancement of their photoconversion efficiencies (PCEs) which currently lag significantly behind those containing ruthenium-based dyes. The redox mediator in a DSC is responsible for regenerating the ground state of the dye. Although the I3/I couple has become an established redox shuttle, it has disadvantages: its redox potential limits the values of the open-circuit voltage (VOC) in the DSC and its use creates a corrosive chemical environment within the DSC which impacts upon the long-term stability of the cells. First row d-block metal coordination compounds, especially those containing cobalt, and copper, have come to the fore in the development of alternative redox mediators and we detail the progress in this field over the last decade, with particular attention to Cu2+/Cu+ redox mediators which, when coupled with appropriate dyes, have achieved VOC values in excess of 1000 mV. We also draw attention to aspects of the recyclability of DSCs.

Graphical abstract: Solar energy conversion using first row d-block metal coordination compound sensitizers and redox mediators

Article information

Article type
Review Article
Submitted
06 Dec 2021
Accepted
05 Jan 2022
First published
05 Jan 2022
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2022,13, 1225-1262

Solar energy conversion using first row d-block metal coordination compound sensitizers and redox mediators

C. E. Housecroft and E. C. Constable, Chem. Sci., 2022, 13, 1225 DOI: 10.1039/D1SC06828H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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