Dye-sensitized Solar Cells System Research Articles

Poly(triphenylamine-thiazolo[5,4-d]thiazole) copolymer dyes with different anchoring end groups: Synthesis, dye-sensitized solar cell (DSSC) performance and femtosecond excited state absorption spectroscopy

In this study, the poly(triphenylaminethiazolo[5,4-d]thiazole) copolymer dyes having the different anchoring end groups of aldehyde (poly-TPATT-CHO; P5), sulfonic acid (poly-TPATT-SO3H; P5S) and cyanoacrylic acid (poly-TPATT-COOH; P5C) have been synthesized and used as sensitizers in dye-sensitized solar cells (DSSCs). The effects of the anchoring end groups of the P5, P5S and P5C copolymer dyes on the DSSC performance were examined. The synthesized copolymer dyes were characterized using 1H NMR, UV–vis. absorption and fluorescence (FL) emission spectroscopy, cyclic voltammetry (CV), MALDI-TOF-MS and FE-SEM-EDS methods. Among the studied polymers, the P5C polymer dye exhibited the best photovoltaic performance with a JSC of 6.46 mA cm−2, a VOC of 0.667 V, a FF of 0.70, and an overall power conversion efficiency (PCE) of 3.02 % under standard AM 1.5 G solar light conditions. These results are attributed to the strong binding ability of cyanoacrylic acid to the TiO2, leading to a greater photocurrent and hindered charge recombination. The effect of electron transfer mechanisms of the polymers on the DSSC performance have been investigated using the femtosecond transient absorption (fs TA) spectroscopy. The DSSC performance of the poly(triphenylaminethiazolo[5,4-d]thiazole) increased greatly by the presence of the cyanoacrylic acid anchoring end group in P5C polymer dye. The fs TA spectroscopy results revealed the presence of singlet–triplet transition for the P5C copolymer dye, while the P5 and P5S copolymers showed only singlet–singlet transitions. The observed triplet state transition in the P5C polymer increased the yield of the DSSC system.

Boosting DSSC efficiency via acid-base co-sensitization with N-1 dye

This work presents a comprehensive investigation of a novel organic dye, N-1, as a sensitizer and co-sensitizer in dye-sensitized solar cells (DSSCs) co-sensitized with Ru (II)-based N3 and N719 metal dyes. These co-sensitizers contain a carbazole ring as a donor scaffold linked to an electron-withdrawing pyridyl acceptor. In this study, we demonstrate the significant impact of a base dye (N-1) containing a pyridine anchoring unit on the photovoltaic performance of the standard dyes N3 and N719. This strategy takes advantage of the capacity of the carboxylic and pyridine moieties to attach to the Brønsted-acidic and Lewis-acidic positions of TiO2 interfaces, thereby diminishing the competing adsorption of dyes and augmenting dye deposition on TiO2 surfaces. Consequently, this leads to a reduction in electron recombination and a boost in photovoltage. Additionally, the effect of sensitizer/co-sensitizer concentration on device performance was thoroughly examined. The results indicated that devices fabricated using the co-sensitizer N-1 with sensitizers N3 and N719 at all concentrations outperformed N3 and N719. Notably, the best photovoltaic performance was obtained for the co-sensitized device fabricated using 0.3 mM acid-base N-1 along with N3 sensitizer, displaying a power conversion efficiency of 10.18 % with a short-circuit current density of 19.12 mA.cm−2, open-circuit voltage of 750 mV, and fill factor of 71 %. These findings shed light on the development of new and efficient systems for DSSCs.

Effect of modified titanium dioxide photoanode and agarose gel electrolyte on electrochemical studies of dye-sensitized solar cell

Recently, the study of new DSSC structures such as photoanodes, electrolytes, and counter electrodes (CE) have gained the attention of researchers. Combining these features allows DSSC to have a flexible and versatile way of working. Titanium dioxide-graphene (TiO2-G) nanocomposite containing 3 wt % graphene (G) was successfully fabricated and employed as the photoanode for the fabrication of a dye-sensitized solar cell (DSSC). Agarose (3 wt %) together with potassium iodide (KI) were prepared as gel electrolytes and polyaniline-graphene oxide (PANI-GO) served as the counter electrode (CE). In UV–visible spectroscopy, doping of graphene on TiO2 led to a remarkable reduction of the band gap energy from 3.0 eV (TiO2) to 2.4 eV (TiO2-G). The presence of agarose in the KI solution facilitated the creation of fine channels, promoting ionic transfer in electrolytes, as revealed by field emission scanning electron microscopy (FESEM). Moreover, the current-voltage (I–V) curve for TiO2-G/3 wt % agarose gel electrolyte/PANI-GO demonstrated a power conversion efficiency (PCE) value of 1.1324% with optimal values for short circuit current density (JSC), open circuit voltage (VOC), and fill factor (FF) of 34.48 mA/cm2, 0.1105 V, and 0.2972, respectively. Cyclic voltammetry (CV) illustrated redox potential occurrences at −0.2 V and +0.2 V, corresponding to oxidation and reduction processes, confirming the chemical stability of DSSC. The system demonstrated stability after 10 cycles, maintaining consistent current (μA) and voltage (V) patterns even after 20 cycles. These results demonstrate the efficient and cost-effective DSSC system's capacity to maintain stability and guarantee consistent energy conversion.

Exploring the potential of porphyrin-based materials for organic solar cells supported on carbon: A quantum chemistry approach

In this work, novel solar cell materials are studied by using first-principle calculations to improve the electronic structure properties and thus enhance the hypothetical efficiency in the active layer of dye-sensitized solar cells (DSSCs). The modeling of 75 composite systems is explored, based on the interaction of three molecular structures; namely graphene, a linker, and metalated porphyrins (a base species and the coordinated cases with Mg, Cu, Ni, and Zn). The stability and electronic structure properties of 10 composite systems, screened from the original set, were analyzed as potential candidates to be implemented in solar cell devices. All calculations were performed using density functional theory (DFT). This study is intended to screen systems that broaden the range of the absorption spectra in the composite materials of the form porphyrin/carbon by improving the electron transfer properties. The methodology to obtain the final set of selected composite materials may be considered a guide in the design of novel DSSC systems.

Effect of natural dye combination and pH extraction on the performance of dye-sensitized photovoltaics solar cell

Dyes are significant components in Dye Sensitized Solar Cell (DSSC) performance because they act as photosensitizers. Natural dye-based DSSC system fabrication innovations continue to be produced in an effort to improve DSSC performance efficiency. In this study, a DSSC system was developed using double components of natural dyes as natural photosensitizers to enhance DSSC efficiency. This method of making natural dye-based DSSC uses a combination of dye extracts from two different dye sources that have the potential as natural photosensitizers in DSSC. The research aims to investigate the impact of the combined use of two natural dyes and pH variations on DSSC performance. DSSC performance measurements encompass the short-circuit current (Isc), open-circuit voltage (Voc), and DSSC efficiency parameters. The obtained results indicate efficiency values for dyes (a) sappan wood/ethanol and turmeric/methanol; (b) turmeric/methanol and beetroot/ethanol; and (c) beetroot/ethanol and turmeric/distilled water. At neutral pH, the efficiency values are 2.09%, 2.10%, and 2.19%, respectively. Meanwhile, at acidic pH of 2.59%; 2.39%; and 2.71%. Notably, the dye efficiency values at acidic pH surpass those found at neutral pH conditions. The highest efficiency is observed in the combination of dye (c) beetroot/ethanol and turmeric/distilled water with efficiency reaching 2.71% at acidic pH.

Dye‐Sensitized Solar Cells Inspired Method to Modulate Photo‐Induced Charge Transfer Efficiency for Enhancing the SERS Activity of Semiconductor

AbstractWhile the Lithium ion modification strategy is widely adopted in tuning the bandgap of semiconductors in dye‐sensitized solar cells (DSSCs), such strategy is yet to be applied to semiconductor‐based surface enhanced Raman scattering (SERS), which is also a photo‐induced charge‐transfer (CT) process. Here, a new DSSCs‐inspired modification method is proposed for TiO2 nanoparticles (NPs): through the adsorption of Li+, the surface states of TiO2 NPs are more abundant, so that the SERS intensity and charge transfer of the adsorbed molecule are significantly enhanced. Similar to DSSCs systems, it is found that the conduction band edge and surface state energy level of TiO2 NPs shift downward with increasing Li+ concentration, which facilitates the CT interaction between the molecules and the SERS substrates. The EF can reach to 104, 1–2 degrees higher than previously reported pure semiconductors. This is the first time to use the DSSCs‐inspired Li+ adsorption strategy on TiO2 NPs as SERS substrate to investigate its SERS enhancement effect, which may provide new ideas for the development of semiconductor nanomaterials in the research of SERS substrates.

Preparation of ZnO/TiO2 Nanocomposite Sensitized Mangosteen Rind (Garcinia mangostana L) Dye for Light Harvesting Efficiency in Solar Cell

The preparation of ZnO/TiO2 nanocomposite is done using the sol-gel method for light harvesting in dye-sensitized solar cell (DSSC). The titanium dioxide (TiO2) compound was added with different ratios to the ZnO matrix and measured its effect on solar cells based on the DSSC system. The powder X-ray diffractions of nanocomposite revealed anatase (TiO2­) and wurtzite (ZnO­) phases have the highest peak at 25.26° and 36.97°, respectively. The energy gap was observed by diffuse reflectance-ultra violet (DR-UV) spectroscopy and it revealed that the optimum performance of nanocomposite was 3.16 eV for the 1:2 ratio. The optimum power efficiency was 2.4% with 3.6 cm2 active area, Voc= 788 mV and Isc=3.39 mA, respectively. The scanning electron microscope-energy dispersive X-ray (SEM-EDX) demonstrated the diversity of surface morphology depends on the ratio of TiO2 in the nanocomposite. This shows the addition of TiO2 to the ZnO matrix influenced the structure of the nanocomposite, which can be applied as DSSC electrodes.

Influence of Limonene from Orange Peel in Poly (Ethylene Oxide) PEO/I−/I3− Based Nanocrystalline Dye‐Sensitized Solar Cell

AbstractA novel method of introducing a Limonene obtained from orange fruit skin (Lim) is successfully incorporated in Poly (ethylene oxide) (PEO) with KI and I2 redox couple and employed in a dye‐sensitized solar cell (DSSC). Scanning electron microscopy (SEM), X‐ ray diffraction (XRD) Ultra violet‐visible spectrum (UV‐Visible), Fourier transform infrared spectrum (FTIR), Thermo gravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS) studies described the influence of Lim on ionic conductivity and the photovoltaic properties of the PEO/KI/I2 system. The temperature‐dependent conduction mechanism of ionic motion and ionic interactions as a function of frequency has been studied. The dielectric behavior of the electrolyte samples were carried out over a wide frequency range (∼1 MHz to 20 Hz) at various temperatures. A DSSC system fabricated with the prepared PEO/KI/I2/Lim polymer electrolyte facilitating a fill factor of 0.52, a short‐circuit current density (Jsc) of 14.1 mAcm−2 and an open‐circuit voltage (Voc) of 795 mV yields the achieved solar to electrical energy conversion efficiency of 5.83 % under irradiation of 1 sun (100 mWcm−2). The compound Lim thus effectively enhanced the ionic conductivity of the composite polymer electrolyte and hence the photovoltaic performance of the fabricated DSSC.

Titanium Dioxide Loaded Reduced Graphene Oxide Nanocomposite Film as Counter Electrodes for Dye-Sensitized Solar Cells

The demands on conventional fossil fuels are increasing especially developing countries. The growth of population among countries also put a lot of pressure on coil consumption and resulted effect of greenhouse. These phenomena will dramatically increase the global warming and pollutes the nature of earth. For the worse, it would forming some erratic patterns like flood, draughts, wildfire, and so on. Therefore, renewable solar energy is the key target to reduce the fossil fuel consumption, minimize global warming issues, and involuntary minimizes the erratic weather patterns. Dye-sensitized solar cell (DSSCs) is one of the promising prospects for efficient renewable resources. Most of the researchers were tried to use platinum as counter electrode to perform the photovoltaic studies. However, the platinum material will made higher for the entire fabrication cost. Recently, we demonstrated a counter electrode in DSSCs system using the low-cost titanium dioxide (TiO2) decorated reduced graphene oxide (rGO) nanocomposite film. The TiO2-rGO nanocomposite (TiO2-rGO NC) as counter electrode is addressed to minimize electron losses and hence rapid the rate of dye regeneration at ground state. Practically, TiO2-rGO NC synthesized via one-step hydrothermal method. The crystallinity, functional groups, element composition, and morphology of TiO2-rGO NC were comprehensively studied. One-step hydrothermal method revealed that Ti particles (∼60 nm) have capable bonded with rGO thin film, as agreement with XRD and FTIR results. In DSSCs photovoltaic performance, the optimized power conversion energy (PCE) of TiO2-rGO NC as counter electrode achieved a 2.90%, which achieved a desire performance as comparable with rGO and TiO2. In this work, the low-cost TiO2-rGO NC as counter electrode with suppressed recombination in DSSCs is studied.

Potential evaluation of flexible annular thermoelectric generator in photovoltaic system performance improvement: Energy and exergy perspectives

Photovoltaic cells only can convert a small part of the inlet sunlight into electricity, and the rest part of the sunlight is transformed into heat. The accumulated heat may significantly degrade the photovoltaic cell performance if not removed in time. In this work, a coupling system model composed of a dye-sensitized solar cell (DSSC), a solar selective absorber (SSA) and a flexible annular thermoelectric generator (ATEG) is put forward to broadbandly harvest the inlet sunlight, in which the ATEG simultaneously considers the Thomson effect, Peltier effect and Seebeck effect. Including various irreversible losses in the coupling system, performance indicators for DSSC, ATEG and coupling system are analytically formulated, from which the energy and exergy performance are revealed. The maximum power density, maximum energy and exergy efficiencies of the coupling system can be, respectively, 86.01 W m−2, 29.56% and 31.77%, which are, respectively, 10.52%, 39.24% and 10.54% higher than that of the single DSSC. Numerical calculation results indicate that the Schottky barrier height, thickness of the TiO2 mesoporous oxide, number of ATEGs, annular shape parameter of ATEG, thickness and width of ATEG can be optimized to maximize the power density, energy and exergy efficiencies. Besides, it reveals that the Thomson effect worsens the coupling system performance. The results obtained are helpful to design and run such a real DSSC-ATEG coupling system.

Effects of Activated Carbon Counter Electrode on Bifacial Dye Sensitized Solar Cells (DSSCs)

The losses of solar cells are consisted of electrical losses and optical losses. Optical losses chiefly reduce the short-circuit current. Here we apply bifacial cell approach to increase light absorption and the short-circuit current of dye sensitized solar cells (DSSCs). We have employed activated carbon (AC) as a very low cost counter electrode, an alternative to Pt counter electrode. Addition of dimethyl sulfoxide (DMSO) and titanium carbonitride (TiCN) to AC increase the efficiency of bifacial DSSC at a mirror angle of from 5.10% to and , respectively. These results indicate that AC has the potential to replace Pt as a very low cost counter electrode of bifacial DSSCs. The bifacial DSSC system using double plane mirrors improve PCE to for Pt counter electrode at a mirror angle of , and for AC counter electrode at a mirror angle of , respectively.

Assessment the Technical and Economic Performance of a Window-Integrated PV System Using Third-Generation PV Panels

A window-integrated PV system was proposed that combines the exterior window of a building with PV panels, and its technical and economic performance was analyzed. A residential building in Seoul, South Korea, was used as a reference model, and third-generation PV panels (i.e., dye-sensitized solar cell (DSSC), and organic photovoltaic (OPV) with transparency characteristics) were analyzed. Regarding the technical performance of the PV panels, the window-integrated OPV system installed in household type B generated the most annual electricity (923.34 kWh), and the window-integrated DSSC system installed in household type A generated the least annual electricity (468.70 kWh). However, the window-integrated OPV system installed in household type C generated the most annual electricity per unit area (36.64 kWh/m2) and the DSSC system installed in household type B generated the least annual electricity per unit area (28.78 kWh/m2). In terms of economic performance, the NPV20 and SIR20 increased as the household’s monthly electricity consumption increased and the closer to the south the orientation of the PV panel was. These results show that the window-integrated PV system that used the third-generation PV panel is economically feasible and is expected to be one of the active strategies for achieving net-zero-energy buildings.

Hybridizing photovoltaic cell with direct contact membrane distillation for electricity and freshwater cogeneration: Concept and performance evaluation

Electricity and freshwater are essential for daily routines, and the cogeneration of electricity and freshwater using solar energy is charming in islands and coastal areas. In this work, a novel hybrid system model mainly comprised of a dye-sensitized solar cell (DSSC) and a direct contact membrane distillation (DCMD) is put forward with the aim to harvest the long wavelength light transmitted through the DSSC for freshwater production. Considering various irreversible losses within the system, performance parameters of DSSC, DCMD and hybrid system are mathematically described, from which the hybrid system performance limits are discussed. Numerical calculations show that maximum efficiency and maximum power output density of hybrid system are, respectively, up to 45.35% and 453.52 W m−2, which are, respectively, 814.31% and 482.78% larger than that of stand-alone DSSC. Exhaustive sensitivity analyses are conducted to investigate how the proposed system performance is influenced by some operating conditions and designing parameters. It is found that feed water temperature, flow velocity of feed water and flow velocity of permeate water positively improve the performance of hybrid system, but permeate water temperature and Schottky barrier adversely affect the performance of hybrid system. The performance of hybrid system is further discussed under optimization conditions.

Cu modified ZnO nanoflakes: An efficient visible light-driven photocatalyst and a promising photoanode for dye sensitized solar cell (DSSC)

Zinc oxide (ZnO) with suitable dopant has been reported as a suitable alternative to commercial TiO2, as an efficient photocatalyst and a promising photoanode for dye-sensitized solar cells (DSSCs) application. In this work, Cu doped ZnO nanoflakes with optimal doping have been fabricated for efficient visible light-driven photocatalysis along with promising application in the DSSC system. ZnO with 1 wt % Cu doping showed a significantly improved photocatalytic performance by a factor of 4.66 and 3.25 times under visible and solar irradiation respectively when compared with pristine ZnO. The advantage of ZnO doping with optimal Cu content lies in the fact that it can facilitate the elevated photon absorption along with reduced charge carrier recombination. Additionally, the DSSCs comprise bare ZnO and metal-based dye shows poor performance in terms of power conversion efficiency (PCE). Profiting from the merits of Cu modified ZnO, which prevent the formation of such Zn2+/dye complex, an increase of 3.56 times in PCE is observed for ZnO with optimal Cu doping (1 wt %). Maximum Jsc of 0.81 mA/cm2 is achieved for the ZnO with 1 wt % Cu compare with the Jsc of 0.26 mA/cm2 for the bare ZnO. Interestingly, optimized Cu modified ZnO shows remarkable photocatalytic and photocurrent stability up to a few repeated cycles. The increased photocatalytic and DSSC performance of Cu doped ZnO is discussed in detail based on its different physicochemical properties. Moreover, an expected mechanism is also proposed to explain the superior performance of Cu modified ZnO at optimal content.

A novel hybrid system consisting of a dye-sensitized solar cell and an absorption refrigerator for power and cooling cogeneration

To improve the energy conversion efficiency of a dye-sensitized solar cell (DSSC), a novel hybrid system representatively consisting of a DSSC and an absorption refrigerator (APR) is put forward, in which the APR is used to thermally harness the part of high wavelength sunlight that not converted by the DSSC. The amount of heat from the DSSC is calculated, and mathematical formula for energy conversion efficiencies and output powers of the DSSC, APR and hybrid system are derived. Numerical calculations show that the maximum output power density and maximum energy conversion efficiency of hybrid system are enhanced by 9.93% and 9.92% in comparison with that of the single DSSC, respectively. Integration of APR to DSSC is a feasible route to effectively improve the energy conversion efficiency. Comprehensive sensitivity analyses are conducted to explore how the whole hybrid system performance depends on various working conditions and designing parameters, including porous nano-TiO2 film thickness, photoelectron absorption coefficient, internal irreversibility factor, heat transfer coefficient and various temperatures. The research results can provide some new understandings for further enhancing the DSSC performance.

Theoretical analysis of charge flow rate at dye sensitized-semiconductor interfaces cell system

The dynamics of charge flow at the interface of the Dye/Semiconductor cell has been investigated by a quantum transfer theory. At the interface between the N3 and Cresyl Violet CV dyes complex such as CdS and InAs semiconductor, the potential determines the flow charge transfer rate and indicates the efficiency of the devices. The flow charge rate at N3/CdS, N3/InAs, CV/CdS and CV/InAs were increased along with decreasing the energy of transition and increasing the coupling parameter. The potential at the interface also indicates the effect of the structure of the material on the flow charge rate in the dye-sensitized solar cells (DSSC) devices. The flow charge rate at DSSC system is polar dependent region. In this study, the flow charge rate was found to be highly compared to InAs by factor 102.

Geometric Effect of Grating-Patterned Electrode for High Conversion Efficiency of Dye-Sensitized Solar Cells

Photovoltaic devices that convert solar energy into electrical energy are a promising solution to resolve environmental problems the world is facing today. Among the various photovoltaic system, dye-sensitized solar cells (DSSCs) has been regarded as a new generation of the photovoltaic device due to the low cost and simple fabrication process. However, the current design of DSSCs shows insufficient conversion efficiency. To solve this problem, we increase the optical path length by trapping the incident light using a diffraction grating with high reflectance. We numerically investigate the effect of geometric parameters on the reflectance of diffraction gratings in DSSC system. Based on the simulation results, we propose an optimized geometry of diffraction grating that reflects the outgoing light and traps the incident light. The optimized geometry of the diffraction grating increase in the reflectance about 80% when it is compared to that without the diffraction grating.

A High‐Voltage Molecular‐Engineered Organic Sensitizer–Iron Redox Shuttle Pair: 1.4 V DSSC and 3.3 V SSM‐DSSC Devices

AbstractThe development of high voltage solar cells is an attractive way to use sunlight for solar‐to‐fuel devices, multijunction solar‐to‐electric systems, and to power limited‐area consumer electronics. By designing a low‐oxidation‐potential organic dye (RR9)/redox shuttle (Fe(bpy)33+/2+) pair for dye‐sensitized solar‐cell (DSSC) devices, the highest single device photovoltage (1.42 V) has been realized for a DSSC not relying on doped TiO2. Additionally, Fe(bpy)33+/2+ offers a robust, readily tunable ligand platform for redox potential tuning. RR9 can be regenerated with a low driving force (190 mV), and by utilizing the RR9/Fe(bpy)33+/2+ redox shuttle pair in a subcell for a sequential series multijunction (SSM)‐DSSC system, one of the highest known three subcell photovoltage was attained for any solar‐cell technology (3.34 V, >1.0 V per subcell).

A High-Voltage Molecular-Engineered Organic Sensitizer-Iron Redox Shuttle Pair: 1.4 V DSSC and 3.3 V SSM-DSSC Devices.

The development of high voltage solar cells is an attractive way to use sunlight for solar-to-fuel devices, multijunction solar-to-electric systems, and to power limited-area consumer electronics. By designing a low-oxidation-potential organic dye (RR9)/redox shuttle (Fe(bpy)33+/2+ ) pair for dye-sensitized solar-cell (DSSC) devices, the highest single device photovoltage (1.42 V) has been realized for a DSSC not relying on doped TiO2 . Additionally, Fe(bpy)33+/2+ offers a robust, readily tunable ligand platform for redox potential tuning. RR9 can be regenerated with a low driving force (190 mV), and by utilizing the RR9/Fe(bpy)33+/2+ redox shuttle pair in a subcell for a sequential series multijunction (SSM)-DSSC system, one of the highest known three subcell photovoltage was attained for any solar-cell technology (3.34 V, >1.0 V per subcell).

Ambient air synthesis of multi-layer CVD graphene films for low-cost, efficient counter electrode material in dye-sensitized solar cells

Graphene holds great promise as a substitute counter electrode (CE) material to replace the conventional Pt in dye-sensitized solar cells (DSSCs). However, lengthy chemical processing with hazardous chemicals, high production cost and the poor quality of the graphene flakes produced impedes their utilization as a CE material in DSSCs. Herein, we demonstrate a low-cost synthesis of multi-layer graphene films using a thermal chemical vapour deposition (CVD) process in an ambient-air environment without expensive compressed gases while using a renewable source namely soybean oil. Utilization of our low-cost graphene film in DSSCs exhibits excellent electrocatalytic activity and high electrical conductivity, and thus delivers superior photovoltaic (PV) efficiency compared to the devices fabricated with graphene films produced from commonly adopted chemical methods. Even though no additional treatments such as heteroatom doping are applied, our low-cost graphene showed great promise in DSSCs. Further enhancement in the efficiency of our multi-layer graphene film based DSSCs is readily achievable by applying simple functional treatments (for example SOCl2). Finally, material cost analysis of our multi-layer graphene film compared to commercial Pt electrode suggests that we can reduce the CE material cost by five fold, making our CVD graphene film a realistic option for application in commercial DSSC systems.