Nanoporous Reduced Graphene Oxide and Polymer Composites as Efficient Counter Electrodes in Dye-Sensitized Solar Cells

Abstract

The introduction of an efficient and precious platinum (Pt) free counter electrode (CE) for dye-sensitized solar cells (DSSCs) is an important aspect to address. In this report, we have employed nanoporous reduced graphene oxide (PG) containing PEDOT:PSS–PG composite on FTO substrate as CEs, which have shown excellent diffusion of I3 –, remarkable photocatalytic activity, and better device performance along with desired stability. The investigated cathode material has been prepared by mixing PGs and highly conducting PEDOT:PSS. Experimental measurements and analyses such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and so on indicate that PEDOT:PSS–PG is a promising cathode material for a Pt-free CE in DSSCs. EIS indicates that the PEDOT:PSS–PGs have lower interfacial charge-transfer resistance because of their high electrical conductivity and superior electrocatalytic activity. The achieved photoconversion efficiency (η) of a DSSC employing the Pt-free PEDOT:PSS–PG/FTO CE is 9.57%, which is found to be comparable to that of Pt/FTO CE based DSSC (9.64%) under a simulated solar light illumination of 100 mW/cm2.

Polyaniline/Ag2S–CdS Nanocomposites as Efficient Electrocatalysts for Triiodide Reduction in Dye-Sensitized Solar Cells

“…First, the photoelectrode was prepared by coating a TiO 2 thin film onto an FTO-deposited glass substrate (sheet resistance: 15 Ω sq −1 ; Solaronix). The TiO 2 paste was prepared through mechanical grinding of a mixture of TiO 2 (1 g), aqueous acetic acid (5 wt%, 5 mL), and polyoxyethylene (10) octylphenyl ether (Triton X-100, 0.4 mL). The prepared TiO 2 paste was coated onto the FTO-deposited glass using the doctor blade method [8,9].…”

“…Moreover, Pt-based counter electrodes generally undergo corrosion mediated by the iodine liquid electrolyte, resulting in DSSCs having low stability [5]. Therefore, many alternative materials have been studied as counter electrodes, including conducting polymers [6,7], carbon-based nanocomposites [8][9][10][11][12], and transition metal oxides, nitrides, carbide, selenides, and sulfides [13][14][15][16][17][18][19][20][21].…”

Recent advances in graphene-based materials for dye-sensitized solar cell fabrication

“…Simple and cost-effective polymer/graphene nanocomposites, such as polyaniline (PANI)/graphene, [192][193][194] PANI/rGO, 195,196 PANI/ GO, 197 and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/rGO, 198 have also been employed as counter electrodes in DSSCs, which displayed excellent stability and PCEs of 3.59, 7.45, 7.45, 3.98, 5.47, 6.12 and 9.57%, respectively. This was comparable to the Pt-based devices, and was attributed to a decrease in interfacial charge transfer resistance, owing to the synergy between the high electron-conducting ability of the graphene-based materials and excellent electrocatalytic activity of the conducting polymers.…”

Sodium Molybdate-Assisted Synthesis of a Cobalt Phosphide Hybrid Counter Electrode for Highly Efficient Dye-Sensitized Solar Cells

“…As third-generation solar cells, dye-sensitized solar cells (DSSCs) have the advantages of low cost, environmental friendliness, and requirement of a simple preparation process when compared to the traditional silicon-based solar cells. , The main function of the counter electrode (CE), which is one of the key parts of the DSSCs, is the reduction of oxidation ions in the electrolyte to maintain an equilibrium state of the redox couple in the I – /I 3 – electrolyte. , The typical electrode material is platinum (Pt), which has superior electrocatalytic activity and electrical conductivity. , However, its noble metal property leads to high cost ($4.6/m 2 for a 5 nm thick Pt film) of DSSCs, which tremendously limits the large-scale fabrication of DSSCs . To solve this problem, many non-Pt and low-Pt CE materials have been developed, including carbon materials, carbides, sulfides, conductive polymers, selenides, metals and their composites, and so on. − Compared with the abovementioned CE materials, transition-metal phosphides have been widely used in electrolysis of water and photocatalytic hydrogen evolution reactions due to their efficient electrocatalytic activity for the hydrogen evolution reaction, high mechanical strength, good electrical conductivity, and durability in acidic and basic media − and have been rarely used as CE catalysts for DSSCs. Among these metal phosphides, cobalt phosphide (CoP) has shown good hydrogen evolution reaction catalytic ability, but it showed inferior catalytic activity to those of noble metals. , The introduction of “collaborators” is an effective approach to reduce the adsorption energy and further improve the catalytic performance of CoP.…”