Performance Of Dye-sensitized Solar Cells Research Articles

Dye-sensitized solar cells with aluminum-doped zinc oxide nanoparticles-loaded electrolyte: A breakthrough solution for recombination and hysteresis suppression

Dye-sensitized solar cells (DSCs) suffer from reduced power conversion efficiency due to electron recombination with triiodide (I3−) ions at the photoanode/electrolyte interface. Organic additives are conventionally used in electrolyte to reduce recombination and improve the efficiency of the device. These additives react covalently with iodine (I2) in the electrolyte, leading to a reduction in the concentration of I3− ions. Other inorganic oxides, such as silica (SiO2), titania (TiO2), and magnesia (MgO), have been shown to improve the efficiency of the solar cell. These oxides can adsorb heavy ions to some extent. In this study, we investigated aluminum-doped zinc oxide nanoparticles (AZO NPs) as an inorganic additive with ionic adsorption properties towards I− and I3− anions in the electrolyte. We confirmed the ionic adsorption of AZO NPs through zeta potential and electrochemical impedance measurements. We observed a significant decrease in recombination between photogenerated electrons and electrolyte ions after adding AZO NPs, which resulted in an increase in open circuit voltage (VOC) and fill factor (FF) values. Furthermore, the incorporation of AZO NPs reduced the compelled hysteresis caused by the mismatch in current density-voltage curves for the forward and reverse scan direction. Mott-Schottky analysis confirmed the increase in VOC due to the negative shift in the Fermi level of the TiO2 photoanode. Additionally, open circuit voltage decay measurements indicated a longer electron lifetime at the TiO2/electrolyte interface in AZO NPs loaded electrolyte. Our findings suggest that AZO NPs have potential as an effective inorganic additive for improving the performance of DSCs.

Fluorine-Doped Tin Oxide Thin Films with High Surface Conductance and Low Transparency for Boosting Performance in Dye-Sensitized Solar Cell Applications

Transparent conductive oxide films, like fluorine-doped tin oxide (FTO), are needed for electrochemical devices. FTO films are attractive due to their cost-effectiveness and high-temperature tolerance. Generally, solar cell fabrication requires high transmittance and low-conductivity FTOs. However, achieving both simultaneously poses a fundamental challenge. This study investigates the impact of FTO layer thickness, sheet resistance, transparency, and film morphology on optimizing the performance of dye-sensitized solar cells. To achieve this, a precursor solution containing SnCl4·5H2O and NH4F in isopropanol is sprayed onto a soda-lime glass substrate at 500 °C to form FTO films. The film thickness is varied by repeating the spray cycles. By increasing the number of spray cycles, the sheet resistance of the FTO film improves to ∼1.20 Ω □–1 with the expense of transmittance. The achieved very low sheet resistance of ∼1 Ω □–1 (∼3.54 × 10–4) Ω cm resistivity for the FTO film confirms the promise of this sequential spray pyrolysis technique in preparing highly conductive inert electrodes for various applications. Furthermore, DSCs with low transparency and sheet resistance showed higher-energy conversion efficiencies, challenging the current prerequisite of the requirement of high transmittance. The best efficiency (5.14%) is achieved with FTO films having a 34.2% transmittance and a 3.27 Ω □–1 sheet resistance, outperforming standard FTO films (4.74%) with a 10 Ω □–1 sheet resistance and an ∼83% transmittance. The results indicate that the transparency of FTO is not a dominant factor and carefully controlled light scattering and electrical properties in translucent FTO films would lead to the realization of dye-sensitized solar cells that deliver superior efficiency.

Different Roles between PEDOT:PSS as Counter Electrode and PEDOT:Carrageenan as Electrolyte in Dye-Sensitized Solar Cell Applications: A Systematic Literature Review.

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been mostly used as a counter electrode to give a high performance of dye-sensitized solar cell (DSSC). Recently, PEDOT doped by carrageenan, namely PEDOT:Carrageenan, was introduced as a new material to be applied on DSSC as an electrolyte. PEDOT:Carrageenan has a similar synthesis process as PEDOT:PSS, owing to their similar ester sulphate (-SO3H) groups in both PSS and carrageenan. This review provides an overview of the different roles between PEDOT:PSS as a counter electrode and PEDOT:Carrageenan as an electrolyte for DSSC applications. The synthesis process and characteristics of PEDOT:PSS and PEDOT:Carrageenan were also described in this review. In conclusion, we found that the primary role of PEDOT:PSS as a counter electrode is to transfer electrons back to cell and accelerate redox reaction with its superior electrical conductivity and high electrocatalytic activity. PEDOT:Carrageenan as an electrolyte has not shown the main role for regenerating the dye sensitized at the oxidized state, probably due to its low ionic conductivity. Therefore, PEDOT:Carrageenan still obtained a low performance of DSSC. Additionally, the future perspective and challenges of using PEDOT:Carrageenan as both electrolyte and counter electrode are described in detail.

Enhanced photovoltaic performance of dye-sensitized solar cells using innovative bithienylnicotinonitrile-based organic dyes

This exciting study introduces five cutting-edge bithienylnicotinonitrile-based organic dyes (coded GA-1-5) that were specifically synthesized for use in dye-sensitized solar cells (DSSCs). These dyes boast a D-π-A framework and were designed to manipulate spectral properties and energy levels. The researchers conducted a comprehensive analysis of their optical, electrochemical, photovoltaic, geometrical, and electronic characteristics using both experimental and theoretical methods. The dyes exhibited intense UV–vis absorption with high molar extinction coefficients, making them ideal co-sensitizers for ruthenium-based DSSCs. When tested, the co-sensitized devices demonstrated significantly improved power conversion efficiencies (PCEs) ranging from 6.22% to 9.12%, thanks to their enhanced short-circuit photocurrents (Jsc), which surpassed those of DSSCs sensitized with N3 alone (PCE = 6.20%). Additionally, GA-1-5 compensated for the photocurrent loss caused by I−/I3 in co-sensitization, further improving the Jsc. We also carried out various spectral and electrochemical characterizations to gain a better understanding of the underlying mechanisms. These findings represent a significant advancement in the field of solar cell technology, paving the way for more efficient and sustainable energy solutions.

Novel quinoline-based sensitizers coupled with diethylenetriamine as a new co-adsorbent to improve photovoltaic performance of dye-sensitized solar cells

Two novel metal-free dyes with 2-ethylhexyloxy substituted triphenylamine as the donor, quinoline as the π-conjugated bridge, benzothiadiazole (BIM27) and N-propylbenzotriazole (BIM28) as the auxiliary acceptors and cyanoacrylic acid as the anchoring group were synthesized and used as the sensitizers for dye-sensitized solar cells (DSSCs). It was found that BIM 27 exhibits anti-aggregation ability, whereas BIM28 forms the undesired aggregates. Therefore, chenodeoxycholic acid (CDCA) and diethylenetriamine (DETA) molecules were employed as the co-adsorbents to suppress the dye aggregation of BIM28. The DSSC with DETA exhibited a highest power conversion efficiency (PCE) of 3.89%, a remarkable improvement of 25% compared with 3.11% of the cell fabricated without co-adsorbent, exceeding that of the benchmark CDCA-based cell (3.57%) under AM 1.5G conditions. The small DETA can effectively insert between the bulky dye molecules compared to the large CDCA, resulting a more compact dye packing on TiO2, able to less charge recombination. The results demonstrate that DETA may be more efficient for co-adsorption of the bulky dyes.

The impact of anchoring groups on the efficiency of dye-sensitized solar cells: 2-Cyanoacrylic acid vs. ethyl 2-cyanoacrylate

Due to their promising performance, coumarin-based dyes have been widely used in third-generation dye-sensitized solar cells (DSSCs) and as nonlinear optical (NLO) materials. In this study, we have designed and synthesized coumarin-based sensitizers in conjugation with common phenyl as a π-linker and ethyl-2-cyanoacrylate (SPDSSC 7) and 2-cyanoacrylic acid (SPDSSC 8) as an anchor and determined their DSSC performance. Photovoltaic results showed that 2-cyanoacrylic acid-based sensitizer (SPDSSC 8) performed better than ethyl-2-cyanoacrylate-based sensitizer (SPDSSC 7) which improves with a thicker coating of TiO2. Density functional theory (DFT) results showed an inverse relationship between band-gap (BG) and chemical potential and electrophilicity index but a direct relationship between BG and hardness and hyperhardness. Time dependent-DFT (TD-DFT) showed a similar trend as observed in the experiment. It was also found that first-order hyperpolarizability (β0) and second-order hyperpolarizability (γ) and PCE is related directly through CT properties. Furthermore, calculations of sensitizers@TiO2 revealed that sensitizer with ethyl-2-cyanoacrylate was linked as unidentate and 2-cyanoacrylic acid linked bidentatly to TiO2 clusters. Furthermore, quantitative analysis of the HOMO-LUMO and MEP plots revealed that SPDSSC 8 showed more efficient electron transfer from the sensitizer to the TiO2 cluster than SPDSSC 7. These results were consistent with the calculated Eadsorption for both sensitizers. The monodentate binding of SPDSSC 7 to TiO2 results in inferior charge transfer in the semiconductor’s conduction band, ultimately negatively impacting DSSC performance.

Unique Dye-Sensitized Solar Cell Using Carbon Nanotube Composite Papers with Gel Electrolyte

We propose a unique form of dye-sensitized solar cells (DSSCs), paper DSSCs based on carbon-nanotube (CNT) composite papers, and the use of a gel electrolyte for the paper DSSC. In our previous study, we succeeded in developing the paper DSSC. However, its performance and lifetime were not sufficient. We considered that the problem was the use of liquid-type electrolyte. To improve the performance of the paper DSSC, a gel electrolyte was introduced to increase safety and durability. Here, a polymer gel electrolyte was synthesized using a copolymer of polyethylene glycol (PEG) and polyvinylidene fluoride (PVDF) as a matrix, mixed with iodine and potassium iodide. The resulting paper DSSC had a fill factor (FF, a performance indicator) of 0.248 and a conversion efficiency of 2.43 × 10−5% with an extended working time (lifetime) of more than 110 min. Further modifications were made to the metallic CNT composite paper and the gel electrolyte, resulting in an increased conversion efficiency of 2.02 × 10−3%. This study suggests the potential of gel electrolytes in enhancing the performance of paper DSSCs, providing new insights for their future applications.

Hydrothermally grown MoS2-flowers as low cost counter electrode material for dye sensitized solar cell and electrode modifier for electrochemical sensing of 4-chlorophenol

In present scenario, energy crisis and environmental pollution are the two major concerns which need immediate attention. Design and fabrication of bi-functional materials to deal with the above concerns are the major challenges for scientific community. Herein, we reported the bi-functional properties of the hydrothermally synthesized molybdenum disulfide (MoS2)-flowers to deal with energy and environmental issues related applications. MoS2-flowers were used as counter electrode material for the fabrication of dye-sensitized solar cells (DSSCs). Fabricated DSSCs showed power conversion efficiency (PCE) of 5.7% and open circuit voltage (Voc) of 0.76 V. Furthermore, MoS2-flowers was used as electrode modifier for the construction of 4-chlororhenol (4-CP). This modified MoS2-flowers based working electrode exhibited reasonable performance in terms of limit of detection and selectivity. A low detection limit of 0.39 µM with sensitivity of 11.47 µA/µMcm2 was achieved. MoS2-flowers demonstrated reasonable performance for DSSCs and 4-CP sensing applications.

Polyoxovanadate derived VN@C composite catalysts by different synthesis routes as Pt-free counter electrode for dye-sensitized solar cells

Vanadium-based nitrides have been applied as Pt-free counter electrodes (CEs) electro-catalysts for dye-sensitized solar cells (DSSCs) due to inexpensive cost and easy doping and modification. Herein, polyoxovanadate (NH4)2V6O16 assisted by melamine to prepare VN@C composites by five different synthesis routes, including solvothermal, sol–gel, hydrothermal, ball milling, and chemical mixing method. And then, five VN@C composites were assembled as CEs in the encapsulated DSSCs, and yielded power conversion efficiencies of 4.47, 5.04, 5.35, 5.49 and 6.11% for regenerate traditional I3−/I− shuttles by the photocurrent-photovoltage (J-V) test, respectively. The catalytic performances of VN@C composites CEs were assessed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization experiments, and the significant effects of different synthetic routes were confirmed. The results revealed that VN@C composite CEs prepared by chemical mixing method had higher catalytic performance in DSSCs, which is due to the improvement of conductivity and the high concentration of active sites.

Promoting active sites of Fe3+ ions in SrTiO3 nanosphere: A superior candidate for high performances of Dye-sensitized solar cell and Photocatalytic dye degradation

In the present exploration, the impurity like Fe is doped in the SrTiO3 (STO) in order to enhance the physical properties which in turn used to engineer the material for the specific applications like photoanode in Dye-sensitized solar cell (DSSC) along with the visible-light driven photocatalyst. X-ray diffraction (XRD) confirms the formation of cubic perovskite structured SrTiO3 nanoparticles. The UV-Vis studies reveal that the impurity energy level of the Fe3+ electron could be excited to the conduction band of the SrTiO3, resulting in light absorption in the visible region. The DSSC based on Fe doped STO photoanode shows a lower recombination rate of photogenerated carriers and a longer lifetime, as evidenced by Photoluminescence spectroscopy (PL), Incident Photon to Current Conversion Efficiency (IPCE) and Electrochemical Impedance Spectroscopy (EIS). Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images show the spherical-like morphology. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) revealed the elements present in the material and chemical compositions. When compared with the bare STO photoanode, STF5 photoanode showed two fold increase in the highest power conversion efficiency (PCE) of 3.23 % with an open-circuit voltage (Voc) of 0.72 V, short circuit current (Jsc) of 7.32 mA cm-2, fill factor (FF) of 0.61 and four fold enhancement in IPCE of 41.18 %. Additionally, profit from the merits of STF5 photocatalyst showed a significantly enhanced photocatalytic efficiency (82 %) of methylene blue (MB) degradation under Visible light irradiation. The detailed results are presented and discussed.

Effect of Multilayers CdS Nanocrystalline Thin Films on the Performance of Dye-Sensitized Solar Cells

Due to relatively low price and nontoxicity of photovoltaic (PV) systems, dye-sensitized solar cells (DSSCs) recently gained a lot of attention in terms of improving their performance and longevity. Because most of the major elements are impacted by their separate production and layering procedures, the substances in DSSCs are critical to achieving these goals. Methylene blue dye sensitizer-based solar cells were effectively constructed in this work, and DSSC performance was assessed. The morphologies of nanocrystalline CdS thin films were investigated by the FE-SEM machine, and then XRD patterns of 1 layer, 2 layers, and 3 layers of nanocrystalline CdS thin films were analyzed. The thicknesses of the prepared samples were about 391 nm, 457 nm, and 912 nm for 1, 2, and 3 layers of nanocrystalline CdS thin film, respectively. J-V characteristics of the multilayer CdS thin films have been studied under a 100 mW/cm2 sunlight source. The experimental results revealed that the highest power conversion efficiency of a 3 layer porous-nanowall CdS/MB device was about 0.47%.

Surface plasmon resonance effects of silver nanoparticles in graphene-based dye-sensitized solar cells

Localized surface plasmon resonance (LSPR) has been applied in photovoltaic devices to improve their photoelectric conversion efficiency. In this study, the mechanism of LSPR in dye-sensitized solar cells (DSSCs) was determined. Specifically, silver nanoparticles were formed by evaporating silver in electro-beam equipment and then annealing it in a tube furnace. The sizes of the nanoparticles varied with the changes in their thicknesses during evaporation and annealing. A DSSC-based graphene was designed to consist of different sizes of metal nanoparticles assembled on a cathode electrode. The photon electric performance of the DSSCs, which depended on Ag nanoparticles, was analyzed in detail, with a particular focus on nanoparticle size. Compared with the DSSC without Ag nanoparticles, the DSSC with LSPR exhibited excellent electric current density and incident photon-to-current efficiency (IPCE) performance due to the LSPR effect. The DSSC assembled with 10 nm-thick Ag film and annealed to form nanoparticles exhibited a high IPCE of 70.03%. The IPCE value of this DSSC was 45.15% higher than that of the pure graphene-based DSSC (31.62%). However, Ag nanoparticles increased to a certain degree and became aggregated and concatenated, thereby decreasing the LSPR effect on DSSCs. Therefore, LSPR plays an important role in the photon-electrical performance of DSSCs.

Effects of metal bis(trifluoromethanesulfonyl)imides as dopants of a hole-transporting tercarbazole compound on the photovoltaic performance of solid-state dye-sensitized solar cells

A mixture of 3,3′′,6,6′′-tetrakis(1,1-dimethylethyl)-9′-ethyl-9,3′:6′,9′′-ter-9H-carbazole (TerCz) and 1-methyl-3-propylimidazolium iodine (MPII) was utilized as a hole transporter for solid-state dye-sensitized solar cells (DSSCs). The power conversion efficiency of a solid-state DSSC with magnesium(II) bis(trifluoromethanesulfonyl)imide (MgTFSI2)-doped TerCz/MPII layer was over 70% higher than that of a reference cell with LiTFSI dopant. Superior hole collection and electron injection efficiencies were achieved in the DSSC with the MgTFSI2 dopant, resulting in a much higher short-circuit current than that of the reference device. By doping MgTFSI2, a higher fill factor was also recorded due to a lower series resistance than that of the reference cell.

Hopping transport in triphenylamine and indoline based semiconductors in the context of dye sensitized solar cells: A DFT Study

Dye-sensitized solar cells (DSSCs) have drawn a significant interest due to their low production cost, light weight, better flexibility in design, and better tunability. Herein, two metal free organic dyes based on donor-π-acceptor (D-π-A) type architecture having methoxy substituted triphenyl amine (TPA) and methyl substituted indoline(IND) as the donor units, cyanoacrylic acid (CA) as the acceptor unit, and 8H-thieno [2′, 3′:4,5]thieno[3,2-b]thieno[2,3-d]pyrrole (TTP) unit as π-bridge are successfully designed for fabrication of DSSCs. To tune the optical properties, structural engineering has been carried out at the TTP unit via substituting different +I groups, viz., −H, −CH3, −OCH3, −CH2CH2, −SH, and −OH and different −I groups viz. −CF3, −COCH3, −COOH and −CN. Various structural, electronic and optical parameters are calculated for the designed dyes. Our study reveals that dyes substituted with electron withdrawing groups possess lower ΔH−L values for both TPA−CA and IND−CA groups of dyes. Moreover, the ESOP and GSOP values of all the dyes confirm the spontaneity of the electron injection and dye regeneration processes with respect to the conduction band of the TiO2 surface and redox potential of the I−/I3− redox couple. The absorption properties also manifest the red shift behavior of the designed dyes. Further, from the study of the structural and electronic properties of the dye-Ti5O10 clusters it is evident that the performance of the dyes get increased upon binding to the TiO2 surface. Hence, our study provides a good recommendation for further designing of dyes to enhance the performance of DSSCs.

The effect of central transition metals and electron-donating substituent on the performances of dye/TiO2 interface for dye-sensitized solar cells applications

Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) approaches were applied to explore the effect of central transition metals and the dye/TiO2 interface on dye-sensitized solar cell (DSSC) performance and supply a promising way to estimate and screen possible candidates for DSSC applications. The interaction properties, bonding characteristics, sensitized mechanisms, charge transfer, frontier molecular orbitals, energy gap, partial densities of states (PDOS), non-covalent interactions (NCI), and electronic absorption spectra were examined and analyzed to provide the photovoltaic characteristics of Sc, Cu, and Ti tetrasulfonic acid phthalocyanine sensitizer@TiO2 interface in both gas phase and polar solvent as acetonitrile.The interfacial of TiPc-(SO3H)4 with TiO2, which facilitates the driving force for the electron injection of photosensitizers (ΔGinj), increases the charge separation, open-circuit voltage (Voc), and high light-harvesting efficiency (LHE) values. However, minimize the charge recombination, lifetime of the excited state (τ), regeneration driving force (ΔGreg). Our results reveal that TiPc-(SO3H)4@TiO2 is superior to those of ScPc-(SO3H)4, CuPc-(SO3H)4, TiPc-(SO3H)4 and Pc-(SO3H)4/TiO2, indicating the novel TiPc-(SO3H)4@TiO2 interface could be promising candidates for DSSC photovoltaic devices performance. In addition, the static mean polarizability and first hyperpolarizability of all six dyes elucidated that the TiPc-(SO3H)4@TiO2 interface can be regarded as a potential performer in non-linear optical (NLO) properties. These theoretical identifications may provide novel perspectives and instructions for future experimental researchers to promote the synthesis and application of TiPc-(SO3H)4@TiO2 interfaces to improve the photo-to-current conversion efficiency.

Exploring the impact of electron acceptor tuning in D-π-A′-π-A photosensitizers on the photovoltaic performance of acridine-based DSSCs: A DFT/TDDFT perspective

Nine novel organic molecules with D-π-A′-π-A motifs, designated as (Ac-T-Qs-T-CA) and (Ac-T-Bx-T-CA), were proposed as potential photosensitizers for use in dye-sensitized solar cells (DSSCs). These novel organic photosensitizers are comprised of an acridine electron donor (Ac) and a thiophene π-spacer (T), while the electron acceptor unit (A′) is either a substituted quinoxaline (Qs) or a benzo[2,5]diazole-1-heteroatom (Bx), and the anchoring group (A) is 2-cyanoacrylic acid (CA). The influence of electron acceptor (A′) moieties on the electronic, photophysical, thermodynamic and photovoltaic properties of the photosensitizers was analyzed using DFT and TD-DFT calculations. The MM3 force field and CONFLEX conformational search methods were employed to study all possible structural conformations of the photosensitizers. The goal was to identify the lowest energy conformer and gain a better understanding of how the structure conformation and torsional angles of (Ac-T-Qs-T-CA) and (Ac-T-Bx-T-CA) compared to the reference photosensitizer RK1 affect electron injection ability and overall performance of DSSCs. The thermodynamic analysis revealed that the photosensitizers (Ac-T-Q2,3-diOMe-T-CA) and (Ac-T-BtA-T-CA), which contain a 2,3-dimethoxyquinoxaline (Q2,3-diOMe) and a benzo[d][1,2,3]triazole (BtA) acceptor moieties, respectively, exhibit a noteworthy enhancement in their electron-injection free energy (ΔGinj) and a reduction in their recombination-free energy (ΔGrec) values, leading to an improvement in the overall photovoltaic properties of the solar cell when compared to the other photosensitizers. The photovoltaic characteristics of the photosensitizers showed that the photosensitizer (Ac-T-Q2,3-diOMe-T-CA) demonstrated the highest values of open-circuit photovoltage (Voc = 1.41 eV) and light harvesting efficiency (LHE = 0.80 eV) compared to the other (Ac-T-Qs-T-CA) photosensitizers. Similarly, (Ac-T-BtA-T-CA) photosensitizer demonstrated the highest Voc (1.08 eV) and LHE (0.75 eV) among (Ac-T-Bx-T-CA) photosensitizers. The photovoltaic performance of these new photosensitizers outperformed the reference RK1 photosensitizer, which only achieved a Voc of 1.2 eV and LHE of 0.61 eV. Finally, the electronic structures and optical properties of photosensitizers adsorbed on the TiO2 surface were studied to provide more accurate information about their adsorption on the semiconductor surface.

Auspicious energy conversion performance of dye-sensitized solar cells based on Gd2O3-impregnated SmTiO3 perovskite/TiO2 nanocomposite photoelectrodes

Auspicious energy conversion performance of dye-sensitized solar cells based on Gd2O3-impregnated SmTiO3 perovskite/TiO2 nanocomposite photoelectrodes

Photovoltaic Measurement Under Different Illumination of the Dye-Sensitized Solar Cell With the Photoanode Modified by Fe2O3/g-C3N4/TiO2 Heterogeneous Nanofibers Prepared by Electrospinning With Dual Jets

In this study, iron oxide (Fe2O3)/graphitic carbon nitride (g-C3N4)/titanium dioxide (TiO2) nanofibers (NFs) were used as an additional layer on photoanode in dye-sensitized solar cells (DSSCs) to improve the photovoltaic performance of DSSCs. The nanofibers were prepared by electrospinning with double jets. The heterogeneous nanofiber composite mainly includes Fe2O3, g-C3N4, and TiO2. The Fe2O3/g-C3N4/TiO2 NFs were characterized by X-ray diffractometer (XRD), and the surface morphology was observed by a field emission scanning electron microscope (Fe-SEM). The electrochemical impedance spectroscopy (EIS) was applied to analyze the impedance of the cell. The incident photon current efficiency (IPCE) measurements were applied to determine the quantum efficiency, and ultraviolet-visible (UV-Vis) spectrophotometer was applied to observe the dye adsorption and absorption wavelength. To understand the performance of the modified photoanodes in DSSCs, we analyzed the photovoltaic parameters. The results suggest that the addition of Fe2O3/g-C3N4/TiO2 NFs is able to improve the conversion efficiency of the modified DSSCs to 4.81%. In addition, the efficiency under different illumination was also analyzed, and the highest conversion efficiency was 6.81% at 30 mW/cm2.

Controlling the electrocatalytic activities of conducting polymer thin films toward suitability as cost-effective counter electrodes of dye-sensitized solar cells

Role dopant anions and solvents in electropolymerized conducting polymers (CPs) on controlling the morphology of thin films and electrocatalytic activities to judge their suitability as low-cost counter electrodes (CE) of dye-sensitized solar cells ( DSSCs) was systematically investigated. Amongst various CPs such as polyaniline (PANI), polypyrrole (PPy), and PEDOT with sodium dodecyl sulfate (SDS) as a dopant, PEDOT was found to exhibit the best photovoltaic performance with a photoconversion efficiency (PCE) of 6.99 %. This was attributed to the best electrocatalytic activity due to the smallest ΔEp, most minor R1, and nano-morphology-assisted high surface area, as confirmed by CV, EIS, and FE-SEM investigations. Using PEDOT as CP, the nature of dopants such as SDS, TFSI, and ClO4 has also been found to control the electrocatalytic activities and the morphology of the fabricated thin films affecting overall photovoltaic performance DSSCs. Amongst the various CP-based CE fabricated using different dopants and solvents, PEDOT:TFSI thin films prepared in acetonitrile solvent and used as CE exhibited not only the best electrocatalytic activity as CE but also demonstrated the best photovoltaic performance with PCE of 7.0 %, which almost similar to that of DSSC utilizing Pt as CE with PCE of 7.1 %. Therefore, it was concluded that the nature of CP and dopant ions were vital factors in governing the electrocatalytic activities of the thin films to ensure their suitability as CE for optimal functioning and controlling the DSSC performance.

Modification of Flexible Electrodes for P-Type (Nickel Oxide) Dye-Sensitized Solar Cell Performance Based on the Cellulose Nanofiber Film.

The preparation of flexible electrode, including working electrode (WE) and counter electrode (CE), for dye-sensitized solar cells (DSSCs) utilizing metal oxides using environmentally friendly sustainable TEMPO-oxidized cellulose nanofibers (TOCNFs) is reported in this work. A new type of flexible electrode for the DSSCs, which were made of cellulose nanofiber composites with nickel hydroxide [CNF/Ni(OH)2] substrate films and cellulose nanofiber composites with polypyrrole (CNF/PPY). Nickel hydroxide, Ni(OH)2, has been prepared hydrothermally in the presence of TOCNFs, [TOCNF@Ni(OH)2]. Similarly, the conductive polymer substrate has also been prepared from a composite consisting of TOCNF and PPY, TOCNF@ PPY film, by means of polymerization for the CE. Overall, the prepared electrodes both WE from CNF/Ni(OH)2 substrates and CE from the TOCNF@PPY substrate film were revealed as the novelty of this work and which no one has introduced previously. Although NiO nanoparticles (NPs) coated on the Ni(OH)2/TOCNF electrode also produced a good power conversion efficiency, PCE (0.75%); nevertheless, the NiO NP treatment with carbon dots boosted the efficiency up to 1.3%.