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

Abstract

In this study, we report the first application of (4-(tert-butyl) benzyl or 4-methyl benzyl)-substituted 2-(pyridin-2-yl)-1Hbenzo[d]-imidazole coordinated copper and cobalt redox shuttles Cu [((tbb) pbi) 2 ] + 1/ + 2 , Cu [(mbpbi) 2 ] + 1/ + 2 , Co [((tbb) pbi) 3 ] + 2/ + 3 and Co [(mbpbi) 3 ] + 2/ + 3 based xanthan gum gel electrolytes (XGE-1, XGE-2, XGE-3 and XGE-4) in fabrication of Dye sensitized solar cells. Interestingly, XGE-1 and XGE-2 obtained higher efficiency of 4.08 and 3.04 % under 1sun illumination. Specifically, highly donor moiety 4-(tertbutyl)benzyl)-substituted (on NÀ H position) 2-(pyridin-2-yl)-1H-benzo[d]-imidazole ligands coordinated, Cu [((tbb) pbi) 2 ] + 1/ + 2 gel electrolyte achieved best performance due to its appropriate redox potential of 0.80 V versus Normal Hydrogen Electrode. This high performance also confirmed with the interfacial studies of the devices. As per the computational results, the copper redox mediators conquered lower reorganization energy and free energy about (0.11-0.20 & 0.18-0.27 eV) due to the effect of ligands structure. Overall, Cu [((tbb) pbi) 2 ] + 1/ + 2 act as redox shuttle for highly proficient DSSCs.

Review on Functional Electrolyte, Redox Polymers, and Solar Conversions in 3G Emerging Photovoltaic Technologies: Progress and Outlook

“…Redox electrolytes based on cobalt complexes have defined potential ranges ( E 0 = 0.3–1.0 V vs NHE), which may be due to structural variation of the organic ligands . The redox potential varies with position and number of redox centers. , Photovoltage can be maximized by controlling the redox center or redox potential of electrolyte. , In general, low V oc originates from the relatively high redox potential of pristine polysulfide electrolyte, which needs high overpotential for QD regeneration. Therefore, V oc can be maximized through a downshift of redox potential of polysulfide electrolyte in the potential energy levels.…”

Recent Investigations on the Use of Copper Complexes as Molecular Materials for Dye-Sensitized Solar Cells

“…A different approach was followed by Shanmugam et al in 2022 [ 41 ], with the realization of an aqueous DSSC with the organic compound MK-2 as a sensitizer, and copper and cobalt complexes as redox mediators (see Figure 9 for the structure of both dye and redox mediators).…”

“…A different approach was followed by Shanmugam et al in 2022 [41], with the realization of an aqueous DSSC with the organic compound MK-2 as a sensitizer, and copper and cobalt complexes as redox mediators (see Figure 9 for the structure of both The counterelectrodes tested by the authors presented various compositions as a consequence of the different preparation techniques, resulting in different loading and distibution of platinum onto the FTO surface: the lowest and highest amounts of the metal were obtained in the case of TR-Pt_1 and TR-Pt_10 (0.98 and 9.81 µg cm −2 , respectively), but there the metal was randomly distributed in between the FTO grains, thus limiting its effectiveness. Better situations were those with PVA or PVO polymers, since no excessive aggregation was observed on the conductive glass.…”

“…A different approach was followed by Shanmugam et al in 2022 [41], with the realization of an aqueous DSSC with the organic compound MK-2 as a sensitizer, and copper and cobalt complexes as redox mediators (see Figure 9 for the structure of both dye and redox mediators). The Cu-and Co-based complexes shared the same bidentate chelating ligand, namely a benzyl-substituted pyridyl-benzimidazole, with different alkylic substituents in para position on the phenyl ring: a methyl in the case of couples [(mbpbi)2Cu] +/2+ and [(mbpbi)3Co] 2+/3+ , while a tert-butyl was present in [(tbbpbi)2Cu] +/2+ and [(tbbpbi)3Co] 2+/3+ .…”