Inverse Opal Carbons for Counter Electrode of Dye-Sensitized Solar Cells

Abstract

We investigated the fabrication of inverse opal carbon counter electrodes using a colloidal templating method for DSSCs. Specifically, bare inverse opal carbon, mesopore-incoporated inverse opal carbon, and graphitized inverse opal carbon were synthesized and stably dispersed in ethanol solution for spray coating on a FTO substrate. The thickness of the electrode was controlled by the number of coatings, and the average relative thickness was evaluated by measuring the transmittance spectrum. The effect of the counter electrode thickness on the photovoltaic performance of the DSSCs was investigated and analyzed by interfacial charge transfer resistance (R(CT)) under EIS measurement. The effect of the surface area and conductivity of the inverse opal was also investigated by considering the increase in surface area due to the mesopore in the inverse opal carbon and conductivity by graphitization of the carbon matrix. The results showed that the FF and thereby the efficiency of DSSCs were increased as the electrode thickness increased. Consequently, the larger FF and thereby the greater efficiency of the DSSCs were achieved for mIOC and gIOC compared to IOC, which was attributed to the lower R(CT). Finally, compared to a conventional Pt counter electrode, the inverse opal-based carbon showed a comparable efficiency upon application to DSSCs.

Poly(3,4-Ethylenedioxythiophene) Inverse Opal Electrode Fabricated from Poly(3,4-Ethylenedioxythiophene):Poly(Styrene Sulfonate)-Filled Polystyrene Template for Dye-Sensitized Solar Cells

“…Less than 10% shrinkage of the air-filled spheres was observed compared to that of the PS opal template. This electrode with an ordered macroporous structure and airfilled pores provided a high specific surface area and was regarded as a potential candidate for a counter electrode due to its high catalytic efficiency in electrochemical tests [24].…”

“…These properties result from the well-ordered porous structures that provide a large surface area for the redox couple in the electrolyte. Second, the periodic nanostructures with long-range ordering also provide much easier electron transfer due to the better interconnections of the ordered structure [23,24]. Here, we prepared an inverse-opal-structured PEDOT electrode by electropolymerization of EDOT onto self-assembled polystyrene (PS), which was deposited on to an FTO glass substrate.…”

“…This PS opal template was a self-assembled electrode that was prepared in a poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) aqueous solution. There has been a report [24] using an inverse-opal structure as a counter electrode, but it included the additional processes of milling and spraying to make thin films. In contrast, we directly deposited inverse-opal-structured PEDOT and used it as a counter electrode without any extra processing to maintain the inverse-opal structure.…”

In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells

“…This has promoted large research interest in exploring alternative counter electrode materials for Pt-free DSSCs. In the past decades, carbon-based materials2345678, conducting polymers69 and transition metal based inorganic materials101112 have been used as counter electrode materials and they showed reliable conversion efficiencies in DSSCs like Pt-based counter electrode.…”

High electro-catalytic counter electrode based on three-dimensional conductive grid for dye-sensitized solar cell

“…The former one is the decisive step [10]. The CE works as an important part in improving the cell efficiency, which was studied to achieve high conductivity and excellent electro-catalytic properties [11].…”