TiO2 Photoanode Research Articles

Boosted Photoelectrochemical Water Oxidation Performance with a Quaternary Heterostructure: CoFe2O4/MWCNT-Doped MIL-100(Fe)/TiO2

Cobalt ferrite (CoFe2O4) combined with multi-walled carbon nanotubes (MWCNTs) is an outstanding material regarding photoelectrochemical water oxidation (PEC-WO) because of its excellent catalytic properties and stability. On the other hand, surface imperfections in CoFe2O4 can cause band bending and surface Fermi level pinning, significantly reducing its PEC conversion efficiency. Heterostructure engineering is essential for achieving increased light-gathering capacity and charge separation efficiency for PEC-WO. In this study, a quaternary heterostructure of CoFe2O4/MWCNT-doped Metal–Organic Framework-100 (Iron), MIL-100(Fe)/Titanium Oxide (TiO2) was synthesized by using a combination of hydrothermal, solvothermal, and “dip and dry” techniques. Characterization results confirmed the formation of a structural network of MIL-100(Fe) on TiO2 surfaces, enhanced by the incorporation of MWCNTs during the hydrothermal reaction. Under 1 sun irradiation, the resultant quaternary heterostructure displayed a photocurrent density (Jph) of 3.70 mA cm−2 under free bias voltage, which is around 3.08 times more than that of pristine TiO2 photoanodes (Jph = 1.20 mA cm−2). This investigation highlights the advantages of the MIL-100(Fe) network in improving the solar PEC-WO performance of TiO2 photoanodes.

Enhancing the Efficiency of Solar Cells Based on TiO2 and ZnO Photoanodes Through Copper Oxide: A Comparative Study Using Vitis labrusca Extract and N3 Ruthenium Dye

This study investigates the effects of varying CuO doping concentrations on the performance of titanium dioxide (TiO2)-based or zinc oxide (ZnO)-based dye-sensitized solar cells (DSSCs). TiO2 or ZnO mixed with CuO at different weight percentages (0–50 wt %) was employed as photoanodes in DSSCs, prepared via mechanical mixing. X-ray diffraction analysis revealed the structural changes, showing that as the CuO content increased in the hybrid, the CuO peaks (notably at 35.5° and 38.7°) became more prominent. Morphological and elemental characterizations were conducted using SEM and XRF, respectively. The solar cells were photosensitized by Vitis lasbrusca (V.L.) extract and N3 dye. The presence of anthocyanin molecules in the extracted V.L. was confirmed using UV-VIS and FTIR spectroscopy. The electrochemical characterization demonstrated optimal solar conversion efficiencies at a 20% doping level for both photosensitizers. Specifically, in the V.L. dye, TiO2-CuO achieved a conversion efficiency of 7.18%, and ZnO-CuO reached 5.77%. In the N3 dye, TiO2-CuO showed an efficiency of 11.34%, and ZnO-CuO, 9.55%. Notably, undoped photoanodes displayed a significantly lower photovoltaic performance: for V.L. dye, TiO2 showed 1.12% and ZnO 0.87%; for N3 dye, TiO2 showed 6.02% and ZnO 4.39%. Doping was therefore effective, yielding up to a seven-fold increase in performance in the case of V.L. with TiO2, compared to undoped DSSCs. The results demonstrate that using the hybrid photoanode led to a considerable increase in performance compared to using only TiO2 or ZnO photoanodes, highlighting the potential of DSSCs as sustainable energy sources.

Synergistic effect of in-situ generated hydrogen peroxide on the degradation of sulfamethoxazole (SMX) by 1T-2H phase MoS2-activated PAA

Activation of peracetic acid (PAA) for pollutants degradation has been a hotspot recently. In this paper, sulfamethoxazole (SMX) is selected as the target pollutant, the degradation system consists of a TiO2 photoanode loaded with 1T-2H phase MoS2 and a nitrogen-doped ZnO cathode. The octahedral coordination and metallic properties of 1T-phase molybdenum disulfide endowed 1T-2H MoS2 with enhanced catalytic performance. Meanwhile, the cathode exhibited outstanding capabilities in generating H2O2 and facilitating its decomposition. In a weakly acidic environment, the SMX removal ratio of the 1T-2H MoS2/N-ZnO/PAA system within 30 min is 96.8 %, which is significantly higher than that of the 1T-2H MoS2/Pt/PAA system at 44.9 % and the 1T-2H MoS2/N-ZnO system at 33.1 %. After OH quenching, the degradation rate of PAA was found to significantly decrease, while the degradation rate of SMX remained almost unchanged. This suggests the hydroxyl radical (OH) preferentially reacts with PAA, leading to the formation of CH3C(O)OO rather than attacking SMX. This co-activation accelerates the formation of CH3C(O)OO and further promotes the degradation of SMX. Overall, this study systematically investigated the overlooked but crucial role of H2O2 in the decomposition of PAA process, which might provide valuable insights for better understanding the underlying mechanism in catalyzed PAA processes.

Surface modification of TiO2 photoanode in dye-sensitized solar cells using reduced graphene oxide: A computational and experimental study

This study investigated the modification of TiO2 photoanodes using reduced graphene oxide (rGO) to enhance electron transport channels and prevent recombination processes, thereby improving the photovoltaic performance. Through the ultraviolet (UV)-assisted photoreduction of GO on TiO2 coated on a fluoride tin oxide substrate (FTO|TiO2), we demonstrated the successful integration of rGO. This was evidenced by the increased Csp2 content observed during X-ray photoelectron spectroscopy and reduced photogenerated electron–hole recombination observed during photoluminescence spectroscopy. The incorporation of rGO significantly improved the photocurrent density and power conversion efficiency (PCE). A 12 % increase was observed in the PCE, which reached 8.5 % when the UV irradiation time was optimized from 10 to 15 min compared with the 7.57 % in the standard cell (rGO-0 min). Electrochemical impedance spectroscopy confirmed that the optimized rGO content enhanced the electron lifetime and recombination resistance, attributable to the high conductivity and large specific surface area of rGO. DFT simulation further elucidated how improved charge separation and transport mechanisms of TiO2–rGO heterojunction. This study highlights the potential of TiO2–rGO materials as promising electrodes for improving the efficiency, capacity, and stability of dye-sensitized solar cells.

A Z-scheme g-C3N4/TiO2 heterojunction for enhanced performance in protecting magnesium and nickel couple from galvanic corrosion

Large interfacial contact is crucial for designing novel heterostructure materials to achieve good photoelectrochemical performance. Herein, we prepared a composite photoanode consisting of titanium dioxide (TiO2) nanotubes and graphitic carbon nitride (g-C3N4) nanosheets for enhancing the photocathodic protection (PCP) capability of the nickel-coated Mg alloy (Mg/Ni). The composite g-C3N4/TiO2 (CN/TiO2) photoanode was achieved by depositing g-C3N4 on the TiO2 nanotubes grown titanium foil via a one-step thermal polymerization of melamine and thiourea mixture. A series of characterizations, including transmission electron microscope, X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectra, manifested the successful deposition of g-C3N4 at the inner wall of the TiO2 nanotubes to achieve sufficient interfacial contact and the formation of a Z-scheme heterojunction to promote the charge carriers’ transfer and separation. Compared with the pure TiO2 photoanode, the heterojunction exhibited enhanced photoelectrochemical and photocathodic protection performances, which was confirmed by the electrochemical measurements. The heterojunction achieved a duration of 6.5 h to protect the Mg-Ni couple from galvanic corrosion, representing a tenfold enhancement compared with the uncoupled Mg/Ni electrode. These findings demonstrate the great potential of constructing a unique Z-scheme heterojunction with a sizeable interfacial contact area to enhance the PCP capability of metals.

Enhancing photovoltaic performance of dye-sensitized solar cells through TiO2/g-C3N4 nanocomposite photoanodes for improved charge carrier management

This study explores the enhancement of dye-sensitized solar cells (DSSCs) through the modification of porous TiO2 photoanodes by incorporating two-dimensional graphitic carbon nitride (g-C3N4) synthesized from urea. The combination of wide-bandgap TiO2 with narrow-bandgap g-C₃N₄ extends the optical response range of the TiO2 heterostructure composites from ultraviolet to visible light. The introduction of g-C3N4 with TiO2 to form a heterojunction significantly boosts the photovoltaic performance of the device by minimizing charge recombination at the photoanode-electrolyte interface. Upon optimizing the g-C3N4 loading, a peak power conversion efficiency (PCE) of 10.79 % is achieved, representing an impressive 42 % improvement over the pristine TiO2-based device. This enhancement is primarily attributed to the efficient separation of photogenerated charge carriers, facilitated by the type II band alignment between g-C3N4 and TiO2. This alignment, enabled by favorable conduction and valence band offsets, accelerates the separation of photogenerated carriers and prolongs electron lifetime.

Application of NiS modified WS2/TiO2 heterostructure in photocathodic protection

Stainless steel, as a popular corrosion resistant material, is still vulnerable to pitting corrosion in the marine environment. Therefore, in order to ensure the safety of stainless steel in the marine environment, it is necessary to implement corresponding protective measures. Titanium dioxide (TiO2), as an N-type semiconductor with excellent photoelectric properties, is widely used in the field of cathodic protection. However, as a photogenerated cathodic corrosion protection material, TiO2has the disadvantages of low conductivity and high carrier recombination rate. Therefore, WS2and NIS were introduced in this paper to modify it. TiO2/WS2/NiS (TWN) composites with Type-Ⅱ heterojunction structure were prepared by hydrothermal method and titration method. The results reveal TWN5 showed the best photoelectrochemical (PEC) performance, and the photocurrent density was 69% higher than that of a pure TiO2photoanode, and the photochemical and photocathodic protection performance was significantly better than that of pure TiO2. Under simulated ocean conditions, the self-corrosion potential of 304ss combined with TW5 and TWN5 photoanodes is reduced to -0.64 V and -0.7 V, respectively. The main reason is that the contact surfaces of WS2and TiO2formed a Type II heterostructure, which accelerates the separation and diffusion processes of photoinduced carriers. In addition, the plasmon resonance effect of NiS improves the ability to absorb visible light, and the metallic-like feature of NiS also promotes charge separation.

Structural and photoelectrochemical properties of fibrous silica-titania (FST) photocatalyst for water splitting

Photoelectrochemical (PEC) water splitting is an ecologically friendly technique that uses effective photoanodes to generate hydrogen (H2). The microemulsion approach was used to develop a distinctive form displaying fibrous silica-titania (FST) photoanode. We examined the photocatalytic attributes of FST, hematite (Fe2O3), and zinc oxide (ZnO). XRD, N2 adsorption-desorption, FESEM, TEM, FTIR, XPS, UV–vis/DRS, and EIS were used to investigate the FST, Fe2O3, and ZnO. By using these techniques, a bicontinuous concentric lamellar arrangement with an ample surface area has been developed within FST. Characterization results demonstrate that FST has superior catalytic activity when compared to Fe2O3 and ZnO. The FST photoanode has an improved photocurrent density of 11.75 mA/cm2 and a 14.1% Solar-to-hydrogen (STH %) efficacy, which is greater than ZnO and Fe2O3, which performed at 4.7 mA/cm2 and 2.8 mA/cm2 with 5.6% and 3.36% STH efficiency, respectively. Moreover, we also compared the Solar-to-hydrogen (STH %) effectiveness of FST with different of TiO2 photoanodes. We absorbed that the band gap is decreased when Ti is added to the silica matrix, which facilitates the formation of Si–Ti bonds. FST displays a remarkable closeness of its conduction band (CB) to the hydrogen reduction potential in comparison to ZnO and Fe2O3, allowing for quick electron transfer and rapid production of H2. The geometry of FST design provides a novel way for producing robust and exceptionally productive photoanodes for PEC water splitting.

THE EFFECT OF SPUTTERING TEMPERATURE OF TiO2/ITO-PEN PHOTOANODES IN DYE SENSITIZED SOLAR CELL

Currently, the world is facing a major crisis related to the lack of sustainable, safe, and environmentally friendly energy resources. Dye sensitized solar cells (DSSC), another name for third-generation solar cells, have gained a lot of interest due to ease of production, cheapness, and environmental friendliness. The photoanode is among DSSC's most crucial components. In this research, the active layer on the TiO2 photoanode was optimized to improve the efficiency of the DSSC. The active layer was deposited using Radio Frequency (RF) magnetron sputtering on an Indium tin oxide-polyethylene naphthalate (ITO-PEN) substrate. The sputtering temperature was varied to 25, 80, 120, and 160℃ for one hour. The thin film TiO2/ITO-PEN photoanode will be characterized by means of X-ray Diffraction (XRD), Ultraviolet-Visible (UV-Vis) spectroscopy, and solar simulator. The XRD analysis shows that the best crystal size is 14.55 nm for a sputtering temperature of 80℃. According to the UV-Vis data, optical absorption increases with increasing sputtering temperature. The wavelength range where the absorption peak occurs is 252–465 nm, and the smallest value of the energy gap is found at a sputtering temperature of 25℃ with a value of 3.02 eV. For the TiO2/ITO-PEN thin layer, the maximum efficiency was achieved at 0.12% at a sputtering temperature of 25°C.

Regulating Chlorine and Hydrogen Atom Transfer for Selective Photoelectrochemical C─C Coupling by Cu-coordination Effect at Semiconductor/Electrolyte Interfaces.

Semiconductor-based photoelectrochemical (PEC) organic transformations usually show radical characteristics, in which the reaction selectivity is often difficult to precisely control due to the nonselectivity of radicals. Accordingly, several simple organic reactions (e.g., oxidations of alcohols, aldehydes, and other small molecules) have been widely studied, while more complicated processes like C─C coupling remain challenging. Herein, a synergistic heterogeneous/homogeneous PEC strategy is developed to achieve a controllable radical-induced C─C coupling reaction mediated by the copper-coordination effect at the semiconductor/electrolyte interfaces, which additionally exerts a significant impact on the product regioselectivity. Through experimental studies and theoretical simulations, this study reveals that the copper-chloride complex effectively regulates the formation of chloride radicals, a typical hydrogen atom transfer agent, on semiconductor surfaces and stabilizes the heterogeneous interfaces by suppressing the radical-induced surface passivation. Taking the Minisci reaction (the coupling between 2-phenylquinoline and cyclohexane) as a model, the yield of the target C─C coupling product reaches up to 90% on TiO2 photoanodes with a selectivity of 95% and long-term stability over 100h. Moreover, such a strategy exhibits a broad scope and can be used for the functionalization of various heteroaromatic hydrocarbons.

Effect of Tungsten Doping on the Properties of Titanium Dioxide Dye-Sensitized Solar Cells

Tungsten-doped TiO2 thin films were prepared by sol–gel method on fluorine-doped tin oxide-coated substrates as working electrodes of dye-sensitized solar cells. The influences of different W doping (0, 2, 4, 6, and 8 at%) on the microstructure, optical, and photovoltaic properties of the W-TiO2 thin-film DSSCs were studied by the measurement of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, and electrochemical impedance spectroscopy (EIS). An optimal DSSCs performance was observed with a 6 at% W-doped TiO2 thin film, resulting in a Voc of 0.68 V, a Jsc of 20.2 mA/cm2, an FF of 68.6%, and an efficiency (η) of 9.42%. The efficiency of DSSCs with 6 at% W-doped TiO2 photoanode improved by 75%. This is because the 6 at% W-doped TiO2 thin film increases the specific surface area and electron transfer rate.

Charge carrier dynamics of chemical vapor deposited carbon-doped titanium dioxide photoanodes

This study explores the synthesis of carbon-doped titanium dioxide TiO2(C) photoanodes through a single-step, low-pressure chemical vapor deposition (LCPVD) method, investigating the influence of carbon doping and oxygen vacancies on photoelectrochemical performance. The research employs morphological, structural, and photoelectrochemical characterization methods, including intensity-modulated photocurrent spectroscopy (IMPS) and distribution of relaxation times (DRT) analysis. We correlate the simultaneous presence of surface carbon and oxygen defects to improved charge separation and collection for TiO2(C) photoanodes. This work provides a comprehensive and detailed explanation of the photoelectrochemical performance of TiO2 electrodes, showing the potential behind combined IMPS-DRT analysis for photoelectrode characterization.

Enhancing the photoelectrochemical performance of TiO2 photoanode by employing carbon nanoparticles as electron reservoirs and photothermal materials.

Photoelectrochemical (PEC) water splitting is regarded as a potential technique for converting solar energy. However, the fast charge recombination and slow water oxidation kinetics significantly have hindered its practical application. It is found that an elevation in operation temperature can activate the charge transport in the photoanodes. Here, a strategy was performed that carbon nanoparticles were employed to TiO2 nanorods, acting as electron reservoirs as well as photothermal materials. More specifically, a record photocurrent density of 1.62mAcm-2 at 1.23V vs. RHE has been achieved, accompanied by a high charge separation efficiency of 96% and a long-term durability for 8h. The detailed experimental results reveal that under NIR light irradiation, the synergistic effect between electron storage and temperature rise leads to accelerated charge transport in the bulk and water oxidation kinetics on the surface. This research offers a new perspective on how to boost the PEC performance of photoelectrodes.

The photoelectrochemical properties of FTO/WO3/BiVO4/TiO2 photoanode for water splitting

This work investigates the photoelectrochemical performance of an FTO (Fluorine-doped Tin Oxide) /WO3 (tungsten trioxide) /BiVO4 (bismuth vanadate) /TiO2 (titanium dioxide) photoanode for water splitting. By forming a heterojunction between WO3 and BiVO4, charge separation and transportation are significantly enhanced, resulting in an improved photocurrent density. Surface modification with a thin TiO2 layer further improves the stability of the photoanode without compromising its photocurrent. The SEM, XRD, and XPS analyses confirm the successful formation of the photoanode structure. The photoelectrochemical J-V curves demonstrate that the WO3/BiVO4 composite electrode outperforms single WO3 and BiVO4 electrodes, and the TiO2 coating further enhances its performance. These findings provide valuable insights into optimizing BiVO4-based photoanodes for efficient hydrogen production via water splitting.

Heterophase homojunction construction by amorphous TiOx and N–TiO2 photoanode for oxygen evolution reaction kinetics and charge carriers’ transportation enhancement

Photoelectrochemical (PEC) water splitting by TiO2 photoanode for clean hydrogen production is limited by the poor charge separation and inert oxygen evolution reaction (OER) kinetics issues for now. In this work, a band-matched heterophase homojunction (TiOx/N–TiO2) by amorphous TiOx and N-doped TiO2 nanotube arrays is constructed by two-step anodic oxidation and impregnation. The photocurrent density of TiOx/N–TiO2 reaches 0.69 mA/cm2 at 1.23 V vs. RHE, which is 1.86 folds than bare TiO2. The enhanced charge carriers' injection/separation efficiency, smaller Tafel slope (37.79 mF dec−1) and larger electrochemical active surface area (ECSA) (1.98 mF cm−2) of TiOx/N–TiO2 indicate that N doping and heterophase homojunction with amorphous TiOx effectively facilitate the surface OER kinetics and charge carriers' transportation. TiOx/N–TiO2 is annealed with a transformation of the surface amorphous TiOx layer into anatase TiO2 (a-TiOx/N–TiO2) to study the role of amorphous TiO2 in PEC water splitting. The photocurrent density and applied bias photon-to-current efficiency (ABPE) for a-TiOx/N–TiO2 decrease, even lower than the pristine TiO2. This is due to the reduction of surface oxygen vacancies, which causes the slowdown of OER kinetics and the weakening of charge carrier transportation ability. That is favorable for a better understanding of the OER kinetics and charge carriers’ transportation enhancement mechanism by the surficial modification on the semiconductor during the PEC water splitting.

Visible-light responsive photocatalytic fuel cell with gas-diffusion g-C3N4/TiO2 heterojunction photoanode for simultaneously degrading VOCs and generating electricity

The use of a gas diffusion photoanode for a photocatalytic fuel cell is promising to simultaneously degrade VOCs and generate electricity. However, conventional gas-diffusion photoanode faces the issues of inefficient solar energy utilization and serious electron-hole recombination. Herein, a visible-light-responsive gas-diffusion g-C3N4/TiO2 heterojunction photoanode is developed for simultaneous degradation of toluene and generation of electricity. In addition to the intrinsic feature of reduced mass transfer resistance of VOCs to the photocatalytic surface, such a gas-diffusion photoanode not only extends the photo-response spectrum, but also enhances charge separation. Accordingly, the photocatalytic fuel cell with the newly-developed photoanode demonstrates superior discharging performance and toluene removal efficiency over the gas-diffusion TiO2 and g-C3N4 photoanodes. The maximum power density achieved by the gas-diffusion g-C3N4/TiO2 heterojunction photoanode is 0.0375 mW/cm², while the maximum toluene removal efficiency reaches 43.8 %. This study has promoted the development of photocatalytic fuel cells for the degradation of VOCs and electricity generation.

Novel dual-photoelectrode Z-scheme PEC system for efficient TBBPA removal and debromination: Performance and promoting mechanism

Herein, a novel dual-photoelectrode Z-scheme photoelectrocatalytic system is created to achieve efficient synergistic anodic oxidation and cathodic reduction for TBBPA degradation and debromination. Based on the polydopamine-modified N-doped TiO2 nanotubes (PN-TNTs) photoanode and polydopamine-modified Cu2O nanowires (PC-CNWs) photocathode, the degradation, debromination and mineralization were 99.4%, 77.7% and 52.1% at 0.7 V under visible light for 2 h. The introduction of PDA enhances the visible light absorption by the TiO2 photoanode and protects the Cu2O photocathode from photocorrosion. The main active species identified by electron paramagnetic resonance (EPR) and scavenger experiments as •OH and e− were found to promote the degradation and debromination of TBBPA by oxidation and reduction, respectively. The degradation pathway of TBBPA was determined by Density Functional Theory (DFT) calculations and HPLC-MS analyses. Comparing the intermediates of single and dual chambers, it demonstrated that the photocathode was able to achieve the continuous debromination of TBBPA and intermediates, which reduced the toxicity. Finally, the stability, reusability and energy consumption were evaluated, confirming the feasibility of the system.

Natural dyes (Tithonia diversifolia, Tagetes minuta and Bidens pilosa) sensitized solar cells with reduced graphene based electrodes

The search for suitable alternatives to non-renewable polluting energy sources is a continuous and an active undertaking. There is particular focus towards production of low cost, eco-friendly and more efficient dye sensitized solar cells (DSSCs). Natural dyes DSSCs have the capability of generating green energy at low production cost and hence become a promising class of photovoltaic cells. However, there are inherent problems encountered by the conventional DSSCs including photoanode and cathode related problems such as high cost and electron-hole recombination resulting in a low rate of photoelectric conversion efficiency. In this work, organic dyes from Tithonia diversifolia, Tagetes minuta and Bidens pilosa were used as sensitizers as replacement of synthetic dyes of the conventional DSSCs. The study in addition sought to replace conventional photoanode and cathodes with rGO-TiO2 photo anode and rGO counter electrode. The Tithonia diversifolia has one absorption peak at 665 nm indicating the presence of chlorophyll dye while Tagetes minuta has absorbption peaks at 534 nm suggestive of anthocyanin dye (a flavonoid), 607 nm and 660 nm confirming the presence of chlorophyll a dyes while Bidens pilosa has an absorption peak at 665 nm which again suggests the presence of chlorophyll dye. The tendency of the three natural dyes to absorb in the regions above 650 nm indicates their usefulness for use as dyes for DSSC. The I-V curves of the fabricated natural DSSCs show that when TiO2 is used as the photo anode, Tithonia diversifolia registered a higher efficiency of 0.18 % while Tagetes minuta had the lowest efficiency of 0.08 %. When rGO is incorporated in the TiO2 photo anode, there is an improvement in the solar cell efficiency for all the fabricated DSSCs with Tithonia diversifolia having the highest at 1.56 %. Thus incorporating rGO in the TiO2 photo anode greatly improved the power conversion efficiency of the DSSC. Tithonia diversifolia dye had the highest efficiency which may be attributed to the concentration of the chlorophyll dye.

Effect of electron-donating and -withdrawing substitutions in naphthoquinone sensitizers: The structure engineering of dyes for DSSCs in Quantum Chemical Study

Dye-sensitized solar cells (DSSCs) are cost-effective photovoltaic devices that convert solar energy into electricity using a dye sensitizer, TiO2 photoanode, electrolyte, and counter electrode. This study investigates the impact of substituents on the performance of naphthoquinone-based dye sensitizers in DSSCs. We analyzed various naphthoquinone derivatives’ electronic structures and light absorption properties using DFT and TD-DFT. Our results demonstrate that electron-donating groups enhance DSSC performance by improving light absorption and electron injection. Specifically, naphthoquinone derivatives with methoxy (Dye-2) and methyl (Dye-3) groups showed superior properties. TD-DFT analysis revealed high molar extinction coefficients over a broad spectrum, making these dyes efficient at capturing sunlight. Additionally, these dyes effectively interact with TiO2, which is crucial for photostability and photovoltaic performance. In conclusion, naphthoquinone derivatives with electron-donating groups significantly improve DSSC performance, with Dye-2 and Dye-3 being strong candidates for high-performance applications.

Comparative Study of Quasi-Solid-State Dye-Sensitized Solar Cells Using Z907, N719, Photoactive Phenothiazine Dyes and PVDF-HFP Gel Polymer Electrolytes with Different Molecular Weights

The present study investigates the influence of photosensitizer selection and the polymer electrolyte composition on the performance of quasi-solid-state dye-sensitized solar cells (QsDSSCs). Two benchmark ruthenium dyes, N719 and Z907, alongside a novel photoactive phenothiazine dye were used. Each dye was incorporated into a QsDSSC architecture employing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the gel electrolyte matrix, with varying molecular weights, to investigate their impacts on the overall device performance and long-term stability. Our results demonstrated that the N719 dye exhibited the highest power conversion efficiency (PCE), attributed to its strong absorption in the visible spectrum and efficient electron injection into the TiO2 photoanode. Z907, on the other hand, showed moderate PCE due to its broader absorption profile but slower electron injection kinetics. The phenothiazine dye revealed promising PCE, with tunable absorption properties and efficient charge transfer. Furthermore, the impact of PVDF-HFP polymer gel electrolytes with varying molecular weights on cell stability was explored. The QsDSSC incorporating the PVH80 polymer with the phenothiazine dye exhibited reduced dye desorption, due to the effective dye molecules’ immobilization by the gel matrix, and consequently enhanced long-term stability over 600 h. This comparative study sheds light on the interplay between dye selection, the polymer gel’s properties, and QsDSSCs’ performance. These insights are crucial in designing robust and efficient QsDSSCs for practical applications.