Search Results (6)

In the field of advanced electrical energy conversion and storage, remarkable attention has been given to the development of new, more sustainable electrolytes. In this regard, the combination of redox shuttles with aqueous bio-polymer gels seems to be a valid alternative via which to overcome the typical drawbacks of common liquid electrolytes such as corrosion, volatility or leakage. Despite the promising results obtained so far, redox-active species such as bis(6,6′-dimethyl-2,2′-bipyridine)copper(I) trifluoromethanesulfonylimide, ([Cu(I)(dmby)₂]TFSI), still present inherent challenges associated with their poor water solubility and oxidative lability, which prevents their employment in cheap and sustainable aqueous electrolytes. The present study investigates the stabilization of the Cu(I) complex ([Cu(I)(dmby)₂]TFSI) within two natural hydrogels based on the biopolymers κ-carrageenan and galactomannan, using ZnO nanoparticles as gelling agents. These eco-friendly and biocompatible systems are proposed as potential matrices for quasi-solid electrolytes (QSEs), offering a promising platform for advanced electrolyte design in electrochemical applications. Both hydrogels effectively stabilized and retained the redox species within their networks. In order to shed light on distinct stabilization mechanisms, complementary FTIR and SEM analyses were relevant to reveal the structural rearrangements, specific to each matrix, upon complex incorporation. Furthermore, thermogravimetric analysis confirmed notable thermal resilience in both systems, with the galactomannan-based gel demonstrating enhanced performance. Altogether, this work introduces a novel strategy for embedding copper-based redox couples into gelled electrolytes, paving the way toward their integration in real electrochemical devices, where long-term stability, redox retention, and energy conversion efficiency are critical evaluation criteria. Full article

Three decades ago, dye-sensitized solar cells (DSSCs) emerged as a route for harnessing the sun’s energy and converting it into electricity. Since then, an impressive amount of work has been devoted to improving the global photovoltaic efficiency of DSSCs, trying to optimize all components of the device. Up to now, the best efficiencies have usually been reached with ruthenium(II) photosensitizers, even if in the last few years many classes of organic compounds have shown record efficiencies. However, the future of DSSCs is stringently connected to the research and development of cheaper materials; in particular, the replacement of rare metals with abundant ones is an important topic in view of the long-term sustainability of DSSCs intended to replace the consolidated fossil-based technology. In this context, copper is a valid candidate, being both an alternative to ruthenium in the fabrication of photosensitizers and a material able to replace the common triiodide/iodide redox couple. Thus, recently, some research papers have confirmed the great potential of copper(I) coordination complexes as a cheap and convenient alternative to ruthenium dyes. Similarly, the use of copper compounds as electron transfer mediators for DSSCs can be an excellent way to solve the problems related to the more common I₃⁻/I⁻ redox couple. The goal of this mini-review is to report on the latest research devoted to the use of versatile copper complexes as photosensitizers and electron shuttles in DSSCs. The coverage, from 2022 up to now, illustrates the most recent studies on dye-sensitized solar cells based on copper complexes as molecular materials. Full article

The main goal of this work is to enhance the catalytic performance of PPy and PEDOT films toward the Co²⁺/Co³⁺ redox couple. PPy and PEDOT films were electrodeposited separately on a porous TiO₂ template to assess their suitability as alternative catalysts in dye-sensitized solar cells (DSSC) based on the [Co(bpy)₃]^2+/3+ redox shuttle. The obtained PPy@TiO₂ and PEDOT@TiO₂ counter electrodes displayed much rougher surfaces. Electrochemical studies indicate the superior catalytic activity of both the electrodeposited electrodes toward Co³⁺ reduction, as indicated by lower charge transfer resistance than that of pristine films and even that of Pt electrodes. Therefore, the fabricated DSSC devices with these counter electrodes achieved higher power conversion efficiencies compared to cells with pristine PPy and PEDOT counter electrodes, or even with a Pt counter electrode. Interestingly, the assembled DSSC device with a PEDOT@TiO₂ counter electrode displayed the highest performance among all with a power conversion efficiency of 6.62%, which is better than that obtained by the device with a Pt electrode (6.07%). Full article

Decades ago, we and many other groups showed a nucleo-cytoplasmic translocation of La protein in cultured cells. This shuttling of La protein was seen after UV irradiation, virus infections, hydrogen peroxide exposure and the Fenton reaction based on iron or copper ions. All of these conditions are somehow related to oxidative stress. Unfortunately, these harsh conditions could also cause an artificial release of La protein. Even until today, the shuttling and the cytoplasmic function of La/SS-B is controversially discussed. Moreover, the driving mechanism for the shuttling of La protein remains unclear. Recently, we showed that La protein undergoes redox-dependent conformational changes. Moreover, we developed anti-La monoclonal antibodies (anti-La mAbs), which are specific for either the reduced form of La protein or the oxidized form. Using these tools, here we show that redox-dependent conformational changes are the driving force for the shuttling of La protein. Moreover, we show that translocation of La protein to the cytoplasm can be triggered in a ligand/receptor-dependent manner under physiological conditions. We show that ligands of toll-like receptors lead to a redox-dependent shuttling of La protein. The shuttling of La protein depends on the redox status of the respective cell type. Endothelial cells are usually resistant to the shuttling of La protein, while dendritic cells are highly sensitive. However, the deprivation of intracellular reducing agents in endothelial cells makes endothelial cells sensitive to a redox-dependent shuttling of La protein. Full article

Dye-sensitized solar cells (DSSCs) emerged in the early 1990s as a promising alternative to the classic silicon-based solar cell due to their unique combination of low cost, ease of fabrication, color palette for building integration, and high efficiency in indoor applications. This review article describes the fabrication and the properties of poly (3,4-ethylenedioxythiophene) (PEDOT)-based catalytic counter electrodes (CEs) for DSSCs. In particular, the electrochemical reactivity PEDOT CEs used in conjunction with alternative redox mediators for DSSCs is outlined. Among alternative redox shuttles, cobalt and copper complexes, as well as totally organic thiolate/disulfide, have been considered. Finally, PEDOT can also be used as a hole conductor material in electrolyte-free solid-state dye-sensitized solar cells. This review clearly shows that the progress in DSSCs development is strongly linked to the introduction of PEDOT as a new counter electrode material. Full article

Dye-sensitized solar cells (DSSCs) have been intensely researched for more than two decades. Electrolyte formulations are one of the bottlenecks to their successful commercialization, since these result in trade-offs between the photovoltaic performance and long-term performance stability. The corrosive nature of the redox shuttles in the electrolytes is an additional limitation for industrial-scale production of DSSCs, especially with low cost metallic electrodes. Numerous electrolyte formulations have been developed and tested in various DSSC configurations to address the aforementioned challenges. Here, we comprehensively review the progress on the development and application of electrolytes for DSSCs. We particularly focus on the improvements that have been made in different types of electrolytes, which result in enhanced photovoltaic performance and long-term device stability of DSSCs. Several recently introduced electrolyte materials are reviewed, and the role of electrolytes in different DSSC device designs is critically assessed. To sum up, we provide an overview of recent trends in research on electrolytes for DSSCs and highlight the advantages and limitations of recently reported novel electrolyte compositions for producing low-cost and industrially scalable solar cell technology. Full article