Cathode For Dye-sensitized Solar Cells Research Articles

Nanocomposite Counter‐Electrode Materials for Dye‐Sensitized Solar Cells: A Review

To date, third‐generation solar‐electricity dye‐sensitized solar cells (DSSCs) are a hot research topic for the next generation of photovoltaic solar technology. Additionally, cathodes, including nanocomposite cathode‐based DSSCs, are a crucial component addition to the electrolyte anode. The usage of precious platinum (Pt) cathodes in DSSCs continues to be a barrier for large‐scale DSSCs manufacture. Finding a cost‐effective, environmentally benign, high power conversion efficiency (PCE), and electrocatalytic performance of an alternative Pt‐free nanocomposite cathode material in DSSCs is critical. This review focuses on recent developments in cathode materials, namely, nanocomposite cathodes like polymers/carbon, polymers/transition metal compounds (TMCs), and TMCs/oxide. Furthermore, it also includes the effect of fabrication methods on PCE, morphological structures, and electrocatalytic performance of nanocomposite cathodes in DSSCs, and finally, the conclusion and outlook.

Synthesis of nitrogen and sulfur co-doped reduced graphene oxide by hydrothermal method for fabrication of cathodes in dye-sensitized solar cells

Carbon-based materials have been known as non-metal electrocatalysts with both high performance and low cost for the reduction at the cathode of dye-sensitized solar cells (DSSCs). In this work, nitrogen and sulfur co-doped reduced graphene oxide (NSG) materials were synthesized via using graphene oxide (GO) as a precursor with reducing agent thiourea as the source of providing heteroatoms. Furthermore, NSG materials were extensively prepared via hydrothermal treatment with the investigation of different mass ratios of GO to thiourea. To study the impact of the quantity of reductant on the properties of NSG, reduced graphene oxide (rGO) was prepared by reducing GO with ascorbic acid as a reference sample. Moreover, NSG and rGO cathodes were both prepared by drop-casting method, while platinum (Pt) cathodes were fabricated using commercial Pt paste by screen-printing method. The DSSCs based on NSG cathodes with ratio of GO to thiourea of 1:10 exhibited an efficiency of 7.21 %, which was similar to commercial DSSCs Pt (7.44 %), proving that the judicious heteroatom doping of GO might introduce a potential candidate for increasing performance of DSSCs.

Electronics and coordination engineering of atomic cobalt trapped by oxygen-driven defects for efficient cathode in solar cells

A rational design and the metal coordination environment regulating of single-atom catalysts (SACs) in specific catalytic reaction remain great challenges. The oxygen defective support can be employed as traps to capture metal species, which provides an effective pathway to synthesize SACs. Here, we propose a counterions-assisted oxygen-driven defect capture (CODC) strategy to fabricate a series of atomically dispersed Co-based catalysts with different electronic and coordination environments. When serving as cathode for dye-sensitized solar cells (DSCs), the triiodine reduction reaction (IRR) activity is very sensitive to the coordination structure. Density functional theory (DFT) calculations reveal that the intrinsic electronic distributions, electron-donating ability, and energy level position determine the coordination behavior and catalytic performance of SACs. Our findings not only define an efficient synthetic strategy to a broad class of M-N x C y based SACs for highly-efficient IRR, but also provide an insight for exploring coordination-sensitive reaction from the atomic view. • An electronic and coordination environment control for accelerating the IRR process was developed. • The atomically dispersed Co-based catalysts were synthesized by a counterions-assisted oxygen-driven defect capture strategy. • The IRR catalytic activity was sensitive to the coordination structure of atomic cobalt. • The electron-donating ability and energy level position determined the coordination behavior of SACs by DFT study.

Review of graphene and its modification as cathode for dye-sensitized solar cells

Review of graphene and its modification as cathode for dye-sensitized solar cells

Effect of Synthesis Conditions of Platinum/Reduced Graphene Oxide Nanocomposites on the Electrochemical Behaviors of Cathodes in Dye-Sensitized Solar Cells

This study deals with the preparation and characterization of platinum/reduced graphene oxide (Pt/rGO) as an efficient cathode for dye-sensitized solar cells. Herein, the Pt/rGO material was synthesized by co-precipitation from hexachloroplatinic acid (H2PtCl6) and graphene oxide (GO) precursors. The fabrication of cathodes from Pt/rGO composite paste was carried out using screen-printing paste. The electrochemical behaviors of as-prepared cathodes were analyzed by cyclic voltammetry; the performance of fabricated DSSCs was measured by current density–voltage (J-V) curves and electrochemical impedance spectroscopy. The structural characteristics of the Pt/rGO binary composites were confirmed by Fourier-transform infrared spectroscopy, Raman spectroscopy, x-ray diffraction (XRD), and transmission electron microscopy. Empirical data showed that choosing ascorbic acid as a reducing agent at a ratio of 5:1 between ascorbic acid weight and precursor mixture weight, as well as a GO weight percentage of 20% fabricated DSSCs successfully with a conversion efficiency of 6.25%, which was approximately 90% compared to that of pure commercial Pt material. Characterization results indicated that the Pt nanoparticles were homogeneously distributed on the rGO sheets with an average diameter of less than 25 nm. The Pt/rGO hybrid composite is highly expected to replace Pt in the fabrication of cathodes in DSSCs for low-cost DSSC production in the promising future.

Synthesis of platinum/reduced graphene oxide composite pastes for fabrication of cathodes in dye-sensitized solar cells with screen-printing technology

Platinum/reduced graphene oxide (Pt/rGO) composite materials with different mass ratios were fabricated by thermal decomposition method from H2PtCl6 and reduced graphene oxide (rGO) as precursors. The Pt/rGO composites were used for fabrication of Pt/rGO cathodes by the screen-printing method. The electrochemical properties of the fabricated cathodes were measured using cyclic voltammetry. The dye-sensitized solar cells (DSSCs) were assembled from fabricated cathodes and tested by current density–voltage(J-V) curves and electrochemical impedance spectroscopy (EIS). The results showed that the appropriate replacement amount of rGO for Pt was 20 wt%, with the efficiency of 6.42%, higher than that of commercial Pt cathode. The characterization of the appropriate Pt/rGO composite was investigated by Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. The characterization results demonstrated that Pt/rGO composite material was synthesized and the Pt nanoparticles with size of 10–30 nm were evenly distributed on the rGO sheets. These results indicated that Pt/rGO could be appropriated material to replace Pt in DSSCs in order to reduce the production cost and maintain efficiency.

Nanostructured Mixed Transition Metal Spinel Oxide Thin Films As Efficient Electrocatalysts – Composition, Structure and Properties

Transition metal oxides have received renewed attention with their demonstrated usefulness as cathodes in dye-sensitized solar cells and as anodes in fuel cell [1,2]. In addition, careful choice of the synthesis method and experimental conditions allow for the tailoring of the film nanostructure and surface area. However, it is clear from the literature [3,4] and our own work [5,6] that the experimental parameters used for the oxide material preparation can greatly affect its electrocatalytic properties and this often makes it difficult to compare material performances. We have prepared various spinel oxides, namely CuxCo3-xO4 (0 ≤ x ≤ 1), Ni1-xCuxCo2O4 (0 ≤ x ≤ 0.75) and FeyNix-yCo3-xO4 (for y = 0.1 and 0.15 and x = 1 and 0.5, respectively), on FTO glass using the thermal decomposition method.The films were analyzed, using several structural, chemical and electrochemical methods such as x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). The oxygen evolution reaction (OER) and electroreduction of hydrogen peroxide reaction were used as model reactions to determine the electrocatalytic activity of the electrodes.The SEM analysis shows that the prepared thin films are quite porous and uniform. EDX analysis shows that a good correlation exists between stoichiometric and the resulting composition of the films. CuxCo3-xO4 materials shows a tendency for more copper to be incorporated in the films, while for Ni1-xCuxCo2O4, an excess of Co and a deficiency of Cu is observed. The formation of the spinel structure is confirmed by XRD analysis. For CuxCo3-xO4, an increase of the lattice parameter with increasing copper content was observed. This supports the incorporation of the copper in the spinel structure. However, the increase of the lattice-parameter was not linear due to the formation of copper oxide at higher copper concentrations. For the Ni1-xCuxCo2O4 series, the X-ray data also support the existence of the spinel structure.Using the film's real surface area, as determined by capacitance measurements, it is possible to compare the properties of materials of different roughness. The addition of Cu to Co3O4 to form CuxCo3-xO4 resulted in an increase in roughness for x values from 0.25 to 1. When Ni is added to form the ternary oxides, the roughness more than doubles. For spinel oxides containing iron, nickel and cobalt, the roughness is much lower, i.e., around 80.X-ray Photoelectron Spectroscopy was used extensively to understand cation site occupancy, composition and oxidation state of the metal ions in the ternary oxide materials. Our XPS data shows some differences between the bulk and surface compositions of our materials. The high-resolution spectra for the Co, Cu and Ni 2p peaks indicate the existence of different Co2+/Co3+, Cu+/Cu2+ and Ni2+/Ni3+ ratio for these materials. However, the amount of iron was often too small to be detected by XPS in iron containing samples with y ≤ 0.15. In general, the surface of the materials was found to be enriched with copper and deficient in cobalt. Larger Co2+/Co3+ ratios are usually associated with better electrocatalytic properties towards OER. This points to the octahedral surface sites being the active sites. The analysis of O 1s spectra indicates that it is composed of three components that can be assigned to lattice oxygen, adsorbed oxygen containing species such as hydroxides and surface bonded water.During the presentation, our results will be compared to the morphology, structure, surface and bulk compositions, and electrochemical properties of spinel oxide films of similar compositions reported in the literature.

Fabrication and Electrochemical Behavior Investigation of a Pt-Loaded Reduced Graphene Oxide Composite (Pt@rGO) as a High-Performance Cathode for Dye-Sensitized Solar Cells

A platinum-reduced graphene oxide thin film composite (Pt@rGO, 100 nm) was prepared on a fluorine-doped tin oxide- (FTO-) coated glass substrate by a screen printing method using a Pt@rGO screen printing paste (0.12% Pt;Pt/rGO=1.5 w/w). The as-prepared electrode (denoted as Pt@rGO/FTO) was used as the cathode for the assembly of dye-sensitized solar cells (DSSCs). It showed a well-dispersed and high loading of Pt on rGO surface with a particle size distributed around 10 nm. The redox behavior of ferrocene was performed at Pt/FTO, Pt@rGO/FTO, and rGO/FTO electrodes by a cyclic voltammetry (CV) method. The kinetic parameters, in particular, the standard reduction potential (E0, V), the transfer coefficient (α), the heterogeneous rate constant (k0, cm·s-1), and the diffusion coefficient (D, cm2s-1), were determined by CV data treatment using convolution-deconvolution and fitting methods. The values ofE0,α,k0, andDat Pt@rGO/FTO electrode were, respectively, 326 mV, 0.471, 3.33 cm·s-1, and 4.19 cm2·s-1, equivalent to those of Pt/FTO electrode (340 mV, 0.474, 3.18 cm·s-1, and 4.19 cm2·s-1). The Pt@rGO/FTO electrode exhibited excellent electrocatalytic activity compared to that of Pt thin film (Pt/FTO electrode) prepared from Pt commercial paste. The heterogeneous electron transfer rate constantk0(cm·s-1) for I3-/I-at Pt@rGO/FTO is 1.3 times faster than that at Pt/FTO. The energy conversion efficiency of the DSSCs assembled from Pt@rGO-DSSC cathode reached 7.0%, an increase of 20.7% over the commercial Pt-based cathode (Pt-DSSC, 5.8%). The rGO component in the Pt@rGO composite plays two important roles: (i) facilitating the electron transfer between Pt NPs catalyst and the FTO substrate via the bandgap effect and (ii) the enlargement catalytic surface area of Pt NPs via the loading effect. The rGO material has, therefore, potential to replace the Pt content and improve the performance of the DSSC device.

Improved performance of dye-sensitized solar cells upon sintering of a PEDOT cathode at various temperatures.

Poly(3,4-ethylenedioxythiophene) (PEDOT) thin films have attracted considerable attention as cathodes for dye-sensitized solar cells (DSSCs) due to their air-stable, light-weight and conductive nature. To demonstrate their thermal stability as cathodes, PEDOT thin films coated via electrochemical polymerization on fluorine doped tin oxide (FTO) plates were sintered at different temperatures (50, 100, 150, 200, and 300 °C) for 1 h and a comparison was made with the as-prepared PEDOT thin films. We observed a negative temperature coefficient effect up to 200 °C along with lower surface roughness upon increasing the sintering temperature. Dye solar cells were fabricated using PEDOT thin films (sintered at different temperatures) and as-prepared PEDOT cathodes, and their respective performances were studied. The results showed increased efficiency with the increase in sintering temperatures of the cathode up to 200 °C (η = 4.33%) under the present experimental conditions. Cathodes sintered at 300 °C had poor electrochemical behavior and J–V performance, which may be due to polymer degradation.

Chlorine-Doped Perovskite Oxide: A Platinum-Free Cathode for Dye-Sensitized Solar Cells.

Triiodide/iodide (I3-/I-) redox couple-mediated solar cells, batteries, and electrochromic devices require highly efficient and stable electrocatalysts for I3- reduction reaction (IRR) to overcome performance limitations, whereas the widely used platinum (Pt) cathode for IRR has limitations of high price and unfavorable durability. In this work, we present a halogen element (chlorine) doping strategy to design low-cost perovskite-type electrocatalysts with enhanced IRR activity and stability. The dye-sensitized solar cell (DSSC) assembled by the LaFeO2.965-δCl0.035 cathode delivers an attractive power conversion efficiency (PCE) of 11.4% with a remarkable PCE enhancement factor of 23% compared with Pt, which is higher than most of the reported non-Pt DSSC cathodes. Attractively, LaFeO2.965-δCl0.035 displays superior IRR activity/stability and structural stability in the I3-/I--based electrolyte compared to pristine LaFeO3 because chlorine doping facilitates the creation of oxygen vacancies (active sites) and enhances surface acidity simultaneously. This study provides a new way for designing outstanding IRR electrocatalysts, which could be applied to many redox couple-mediated photo/electrochemical devices.

A carbon nanotube-iron (III) oxide nanocomposite as a cathode in dye-sensitized solar cells: Computational modeling and electrochemical investigations

Here is the evaluating result on the applicability of the multi-walled carbon nanotube (MWCNT) and α-iron (III) oxide (α-Fe2O3) nanocomposite as a cathode material in dye-sensitized solar cells (DSCs). The morphology and the structure of the MWCNT/α-Fe2O3 nanocomposite have characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray elemental mapping analysis. Moreover, the electrochemical performance of the nanocomposite has studied toward the activity of Iˉ/I3ˉ redox couple which represents high current density, low peak-to-peak separation, low charge-transfer resistance, and almost 100% stable response signal. Furthermore, the computational modeling employing the molecular mechanics (MM) and the restricted-Hartree Fock/semiempirical parameterization (RHF/PM6) methods reveals that the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the HOMO-LUMO energy gap of the modeled nanocomposite are as −6.88, −3.62, and 3.26 eV, respectively. These properties match with the electronic-level domino of the DSC structure. Finally, the DSC device has fabricated using N719-sensitized TiO2 photoanode and MWCNT/α-Fe2O3 counter electrode, presenting the open-circuit potential, the short-circuit current density, and the power-conversion efficiency of 0.7 V, 20.37 mA cm−2, and 6.0%, respectively. This study successfully approves the potential of the nanocomposite as a cathode material in iodine-based dye-sensitized solar cells.

An Intrinsically Conductive Phosphorus‐Doped Perovskite Oxide as a New Cathode for High‐Performance Dye‐Sensitized Solar Cells by Providing Internal Conducting Pathways

State‐of‐the‐art dye‐sensitized solar cells (DSSCs) usually use the noble and scarce platinum (Pt) cathode, which strongly limits the practical applications of DSSCs. Accordingly, low‐cost, highly active, and stable alternatives to Pt are highly desired. Herein, an intrinsically conductive perovskite oxide is reported as a new cathode for DSSCs using a simple nonmetal element doping strategy. The phosphorus‐doped perovskite oxide (SrCo0.95P0.05O3−δ [SCP]) shows superior activity/durability for the triiodide (I3−) reduction reaction (IRR) and structural stability relative to the parent compound (SrCoO3−δ [SC]) due to the greatly enhanced electrical conductivity and the stabilization of the perovskite structure. The internal conducting pathways are demonstrated to be very important to obtain high IRR activity of the perovskite cathode, even when the cathode is incorporated with conductive multiwalled carbon nanotubes (MWCNTs). The DSSC with the N719 dye and SCP/MWCNTs cathode displays a superior power conversion efficiency (PCE) of 10.1% to those with Pt (8.11%) and SC/MWCNTs (6.80%) cathodes. In addition, the DSSC with the C101 dye and SCP/MWCNTs cathode shows an attractive PCE of 12.2% with an enhancement of 23%, as compared with the Pt cathode, suggesting that the SCP/MWCNTs composite can be one of the best substitutions to the Pt cathode, which can benefit the future industrialization of DSSCs.

Fabrication of conductive and printable nano carbon ink for wearable electronic and heating fabrics

Printable Nano carbon colloidal ink has fascinated great attention due to their exceptional potential for large-scale application for powering wearable electronic devices. Though, it is challenging to incorporate various characteristics together such as mechanical stability, solution printability, conductivity, electrocatalytic activity, and heat generating properties in the flexible fabric based electrode system. In this research the development of printable composites made with woven/nonwoven fabrics printed with multiwall carbon nanotubes for flexible and wearable heating system and cathodes for dye-sensitized solar cells (DSSC), respectively. We report a printable carbon ink of multiwall carbon nanotubes (MWCNT) synthesized by globular protein serum bovine albumin (BSA). BSA is amino-rich dispersant used to disperse MWCNT and generate tubular porous carbon matrix. High loading ratio of BSA increases the dispersing power of MWCNT and increased porosity of CNT matrix. The proposed Organic Nanocarbon ink (Organic NC) serve the pathways for electron transport leading to higher heat dissipation as the well high conductivity and electrocatalytic activity. It was interesting to reveal that different kinds of woven and nonwoven fabrics displayed exceptional thermal properties when DC voltage was applied. The heat generating properties were highly dependent on the type of fabric and conductive ink uptake. Our proposed Organic NC printed fabric system exhibited superior conductivity with 15–20 Ω resistivity and lower charge transfer resistance RCT = 2.69 Ω, demonstrated an 8% power conversion efficiency of DSSC. The proposed research paves the ways for solution printable high performance woven and nonwoven conductive and thermoelectric materials for wearable electronics.

Rational Design of Metal Oxide–Based Cathodes for Efficient Dye‐Sensitized Solar Cells

AbstractRecently, there is an urgent need for alternative energy resources due to the nonrenewable nature of fossil fuels and increasing CO2 greenhouse gas emissions. The photovoltaic technologies which directly utilize the abundant and sustainable solar energy are critical. Among various photovoltaic devices (solar cells), dye‐sensitized solar cells (DSSCs) have gained increasing attention due to their high efficiency and easy fabrication process in the past decade. The cathode is a critical part in DSSCs while the benchmark Pt cathode suffers from high cost and scarcity. Thus, the development of alternative Pt‐free cathodes has attracted significant attention with the aim to heighten the cost competitiveness of DSSCs. Among various cathodes, metal oxides are of growing interest due to their superior activity, robust stability, and low cost. Simple oxides such as WO3 and SnO2 are used as cathodes for DSSCs. Considering the fixed atomic environment in simple oxides, complex oxides are more attractive as cathodes because of their more flexible physical and chemical properties. This review attempts to present the rational design of simple/complex metal oxide–based cathodes in DSSCs and then to provide useful guidance for the future design of Pt‐free cathodes. The demonstrated design strategies can be extended to other electrocatalysis‐based applications.

A novel carbon bead string cathode for dye-sensitized solar cells

In this study, a novel carbon bead string (CBS) is synthesized through a simple method, which is subsequently introduced into the dye-sensitized solar cells (DSCs) as a cathode catalyst. The resultant CBS cathode displays decent electro-catalytic activities for the traditional iodide redox couple (I3−/I−). More importantly, CBS cathode presents distinct superiorities when applied in an organic sulfide redox couple (T2/T−). T2/T− electrolyte-based DSCs with CBS cathode has resulted in a high power conversion efficiency (PCE) of 5.83%, which is much higher than that of Pt cathode-based counterpart (3.71%), demonstrating 57.1% of PCE improvement.

Facile fabrication of efficient, low-cost Cu2ZnSnSe4 cathode for highly-performance dye-sensitized solar cells

Kesterite-structure Cu2ZnSnSe4 (CZTSe) has been recommended to be a promising Pt-free counter electrode (CE) candidate for dye-sensitized solar cells (DSSCs), owing to its excellent catalytic activity, hierarchical microstructure, and natural abundance. Herein, based on a facile electrodeposition method and mild solvothermal treatment, we prepared great-crystallinity CZTSe nanostructure on FTO substrate as DSSCs cathode directly, demonstrating a satisfied power conversion efficiency of 7.56% and a relatively long-operation life performance. The impressive performance was ascribed from the CZTSe thin film good adhering to conductive substrate, high catalytic activity, effective photo-generated electron migration, and low charge transfer resistance at the interface of the catalytic material and substrate. Our present results prove that the CZTSe nanostructure is a promising and effective Pt-free counter cathode in dye-sensitized solar cells.

The Impact of Metal Ion Doping on the Performance of Flexible Poly(3,4-ethylenedioxythiophene) (PEDOT) Cathode in Dye-Sensitized Solar Cells

Abstract Poly(3,4-ethylenedioxythiophene) (PEDOT) film is synthesized on flexible indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) substrate by electrochemical deposition method. The prepared PEDOT is next used as flexible cathode for dye-sensitized solar cells (DSSCs) toward the regeneration of the triiodide redox couple. The electrochemical results indicate the pristine PEDOT cathode owns a low catalytic activity which can be improved by doping PEDOT with transition metal ions M2+ (M2+ = Mn2+, Co2+, Ni2+, and Cu2+). After optimization, the DSSCs using PEDOT-Mn2+, PEDOT-Ni2+, PEDOT-Co2+, and PEDOT-Cu2+ cathodes generate power conversion efficiencies of 5.19, 4.81, 4.36, and 3.78%, much higher than the pristine PEDOT cathode based counterpart (3.26%).

Insight into the topological defects and dopants in metal-free holey graphene for triiodide reduction in dye-sensitized solar cells

Holey graphene with abundant edge-induced topological defects and nitrogen dopants acts as a durable metal-free cathode for dye-sensitized solar cells.

Efficient electron transfer kuramite Cu3SnS4 nanosheet thin film towards platinum-free cathode in dye-sensitized solar cells

The density-functional theory calculations in this work clearly revealed that the kuramite-structure Cu3SnS4 material possessing the metallic characteristic, result in the higher charge transfer between I3− ions and the Cu3SnS4 surfaces, and the rapid redox transfer reaction of I3−/I− in dye-sensitized solar cells system. Then, a feasible and mild solution method was proposed to in-situ synthesize Cu-rich kuramite-structure Cu3SnS4 thin film on FTO substrate, and the acquired thin film was used directly as counter electrode to assemble dye-sensitized solar cells without any post-treatments. The obtained-Cu3SnS4 nanosheet film had good bonding strength, expanded surface area, low photoelectron charge transfer resistance at the counter electrode/electrolyte interface, and great catalytic activity toward the reduction of I3−/I− ions. Power conversion efficiency of 7.80% was obtained by utilizing Cu3SnS4 nanosheet as counter electrode, which was superior to that of Pt electrode (6.52%). Our results demonstrate the earth-abundant and low-cost kuramite Cu3SnS4 is an alternative Pt-free counter electrode material in dye-sensitized solar cells.

High-surface-area nanomesh graphene with enriched edge sites as efficient metal-free cathodes for dye-sensitized solar cells.

Exploiting cost-effective and highly efficient counter electrodes (CEs) has been a persistent objective for practical application of dye-sensitized solar cells (DSSCs). Here, we present an efficient CE by using pure three-dimensional (3D) nanomesh graphene frameworks (NGFs) which are synthesized via a template-directed chemical vapor deposition (CVD) approach. The high-surface-area 3D NGFs associated with the enriched surface edge defects make it very efficient towards I3(-) reduction even without any Pt catalyst. More interestingly, by virtue of the interpenetrating graphene frameworks, the NGFs exhibit excellent electron conductivity, thus leading to facile charge transfer. Consequently, the DSSCs with pure NGFs as CEs display a power conversion efficiency of 7.32%, which is comparable to that of Pt as CEs (7.28%), thereby exhibiting great potential as low-cost and highly efficient CE materials for large-scale deployment of DSSCs.