High‐Performance Ruthenium Sensitizers Containing Imidazolium Counterions for Efficient Dye Sensitization in Water

Abstract

A new type of water-soluble ruthenium sensitizers incorporating imidazolium counterions, denoted [DMPI] -Ru and [DMHI] -Ru, has been developed, which can be efficiently adsorbed onto TiO photoanodes in aqueous solution. Owing to the good thermal stability of imidazolium, [DMPI] -Ru adsorbed on TiO has a higher decomposition temperature than N719 dye [di(tetrabutylammonium) cis-di(thiocyanato)bis(2,2'-bipyridine-4,4'-dicarboxylato)ruthenium(II)]. When using organic solvent-based I /I electrolytes, solars cell based on [DMPI] -Ru-sensitized TiO in water show high power conversion efficiencies (PCE) of up to 10.2 %, which is higher than that of N719 (9.9 %) under the common conditions for dye sensitization in organic solvent. [DMHI] -Ru, with poorer water solubility than [DMPI] -Ru, gives a smaller dye-adsorption amount on TiO and thus a lower PCE of 9.4 %. From the viewpoint of safety and environmental impact, the fabrication of dye-sensitized solar cells (DSSCs) by using water as solvent is undoubtedly a preferable strategy. Although the [DMPI] -Ru-based device fabricated by using water as the solvent for both the dye-sensitization process and the electrolyte gives a relatively low efficiency, it provides a promising approach for the practical application of DSSCs.

Effect of Copper and Cobalt Metal Complex Redox Mediator Based Xanthan Gum Gel Electrolyte Materials on Performance of Dye Sensitized Solar Cells

“…[34,35] Nevertheless, the chance of combining the liquid solvent with a gel polymer medium can decline the leakage of electrolyte and also rising long-term stability of devices. [36][37][38] As per the previous reports, 50 % and 100 % of water contained polymer gel electrolytes achieved higher PCE of 4.78 % and 5.64 % respectively. [39,40] In our previous work we reported a comparative study on copper and cobalt redox shuttles bearing 4-nitrobenzyl or naphyl-substituted 2-(pyridin-2-yl)-1H-benzo[d]imidazole ligands in organic solvents based liquid electrolytes for DSSCs and achieved a higher PCE of 4.99 % under 1 sun condition.…”

“…To conquer these limitations, water‐based electrolytes are considered as the different idea owing to its environmental benign, low cost, non‐flammability and better stability [34,35] . Nevertheless, the chance of combining the liquid solvent with a gel polymer medium can decline the leakage of electrolyte and also rising long‐term stability of devices [36–38] . As per the previous reports, 50 % and 100 % of water contained polymer gel electrolytes achieved higher PCE of 4.78 % and 5.64 % respectively [39,40] …”

Hydrogel Electrolytes Based on Xanthan Gum: Green Route towards Stable Dye-Sensitized Solar Cells

“…Above all, water-based DSSCs are amongst the best solutions, providing reduced costs, nonflammability, good stability and environmental compatibility [14]. In recent years, scientific literature on this topic has significantly increased [15][16][17][18][19]. Devices have been reported, which achieve efficiency close to 6% with a mixed water/organic electrolyte [20], or even 5.5% and 7% with 100% aqueous electrolytes based on a cobalt [21] and iodine/iodide [22] redox couple, respectively.…”