Electrochemical Impedance Spectroscopy Investigations Research Articles

ELECTROCHEMICAL, DFT AND MULTISCALE SIMULATION STUDIES ON SELF-ASSEMBLED FILMS OF 2-AMINO-4-METHYL-PYRIDINE INHIBITOR FOR COPPER METAL CORROSION PROTECTION IN 3.5% NaCl MEDIUM

Copper metal and its alloys are the most used in the industries because it holds excellent conductivity and natural corrosion protectiveness against air/moisture. However, copper undergoes degradation in presence of aggressive 3.5% NaCl. Protective coating is one of the practical methods to safeguard copper metal. In this study, 2-amino-4-methyl-pyridine (AMP) was coated as self-assembled monolayer method (SAM) with different immersion periods (12 h/24 h) and investigated the corrosion potential against 3.5% NaCl medium. Chemical composition of AMP/SAM/Cu was characterized using Fourier-transform infrared (FT-IR) spectroscopy and morphological analysis using atomic force microscopy (AFM) techniques. AMP’s corrosion inhibition potential were evaluated via electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDS) analyses. Quantum chemical calculations and molecular dynamics (MD) simulations explained the stronger adsorption of AMP over copper metal surface via self-assembly method. The corrosion analysis revealed that AMP’s SAM formation (24 h immersion) enhances the corrosion protection of Cu metal, which is mainly due to the uniform thin adhesive compact layer formation and blocks incoming corrosive chloride ions. EIS investigation evident that AMP forms an adhesive layer over the copper surface and prevents the diffusion of aggressive corrosive medium, while PP studies revealed that AMP acts via the mixed mode of corrosion inhibition mechanism. AMP’s significant inhibition efficiency 90% was confirmed via PP analysis. AFM analysis enabled the morphology image of AMP’s shielding over Cu surface and the molecular modeling investigation supported well for the Cu–N (from AMP) bond formation.

Performance Assessment of Differently Dried Coating Systems for Potential Application in the Power Transformer Industry

Many companies in the power transformer industry are striving to speed up the drying process of coatings, which is why alternative drying methods are constantly being explored while maintaining the same coating protection properties. The infrared (IR) drying of protective coatings is a potential solution for their higher productivity, but has not yet been extensively investigated. In this paper, two solvent-borne coating systems, with and without zinc in the primer, from two different manufacturers, dried by infrared radiation and under atmospheric conditions, were studied. The coating systems consisted of epoxy primer, epoxy intermediate coat, and polyurethane topcoat. Anti-corrosion performance of the coatings was characterized using a salt spray chamber, pull-off adhesion testing, electrochemical impedance spectroscopy (EIS) investigation, and open circuit potential (OCP) measurement. All samples were analyzed using stereo microscope. A scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDX) for detailed study and chemical composition determination was used. The results showed that infrared technology notably reduced coating drying times while maintaining or improving anticorrosion performance properties compared to the coatings dried under atmospheric conditions.

EIS Investigation of the Corrosion Behavior of Steel Bars Embedded into Modified Concretes with Eggshell Contents

This investigation is focused on evaluation of the corrosion behavior of embedded steel bars (SB) into concretes. Conventional and modified concretes with eggshell are prepared. Although the effect of calcium carbonate on mechanical behavior is recognized and reported, their effects as eggshell (ES) particles replacing portions of sand and cement contents are reasonably scarce. Corrosion behavior is evaluated by electrochemical impedance spectroscopy (EIS) and the potentiodynamic polarization technique. Equivalent circuit and porous electrode behavior are also considered. The novelty concerns a promising use of concrete with ES content to maintain corrosion resistance concatenated with reasonable structural properties. For this purpose, three distinct concrete mixtures are proposed, i.e., a reference and two modified concretes. One replaces 10 wt.% with cement and another 10 wt.% with sand content. It is found that porous electrode behavior helps to predict the corrosion mechanism. Finer ES particles in concrete mixture provides a rapidly passivation on rebar. This reflects positively in corrosion current density after long-term immersion. Additionally, an environmentally friendly aspect associated with economical factor constitutes a promise use of the concrete.

Smart self-healing coating based on the highly dispersed silica/carbon nanotube nanomaterial for corrosion protection of steel

The poor dispersion of carbon nanotubes (CNTs) limits their practical enhancement in polymer matrix due to strong Van der Waals force among them and their high aspect ratio. Here, a highly dispersed silica/carbon nanotube (HAC) nanomaterial was prepared, which effectively solved the agglomeration problem of CNTs-based materials. More importantly, X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TG) and UV–vis spectra results confirm that HAC nanomaterials can achieve the loading and release of corrosion inhibitors. Basing on these, we developed a smart self-healing coating system (HACB/EP) to further improve the corrosion resistance of the coating. Electrochemical impedance spectroscopy (EIS) investigation shows that HACB/EP still has the highest low-frequency impedance value compared with other coatings after 30 d of immersion, and the electrochemical self-healing efficiency (ηes) of HACB/EP with an artificial defect (De-HACB/EP) turns into positive values at the second (24–48 h) and third (48–72 h) stage. In general, the enhanced corrosion protection and excellent self-healing performance of HACB/EP will greatly promote the development of smart anticorrosion coatings.

Aggressiveness of Different Ageing Conditions for Three Thick Marine Epoxy Systems

Three different coated steel systems were aged in natural or artificial seawater, in neutral salt spray (NSS), and using alternate immersion tests in order to evaluate the aggressiveness of the different ageing conditions. Commercial epoxy coatings were applied onto steel (S355NL), hot-galvanized steel (HDG), and Zn-Al15 thermal spraying coated steel. The defect-free systems were immersed in artificial seawater at 35 °C for 1085 days and in natural seawater for 1200 days and were characterized by electrochemical impedance spectroscopy (EIS). Panels with artificial defects were immersed for 180 days in artificial seawater and, regarding adhesion, were evaluated according to ISO 16276-2. In parallel, the three coated systems were submitted to cyclic neutral salt spray (NSS) for 1440 h: defect-free panels were regularly evaluated by EIS, while the degree or corrosion was measured onto panels with artificial defect. After NSS, defect-free panels were immersed in artificial seawater at 35 °C for further EIS investigations. Finally, alternate immersion tests were performed for 860 days for the three defect-free coated systems and for 84 days for panels with a defect. The results showed that, for defect-free panels, immersions in natural or artificial seawater and NSS did not allowed us to distinguish the three different systems that show excellent anticorrosion properties. However, during the alternate immersion test, the organic coating system applied onto HDG presented blisters, showing a greater sensitivity to this test than the two other systems. For panels with a defect, NSS allowed to age the coatings more rapidly than monotone conditions, and the coating system applied onto steel presented the highest degree of corrosion. Meanwhile, the coating systems applied onto HDG and the thermal spray metallic coating showed similar behavior. During the alternate immersion test, the three coated systems with a defect showed clearly different behaviors, therefore it was possible to rank the three systems. Finally, it appeared that the alternate immersion test was the most aggressive condition. It was then proposed that a realistic thermal cycling and an artificial defect are needed when performing ageing tests of thick marine organic coating systems in order to properly rank/evaluate the different systems.

Development of a Microbial Fuel Cell Using Methylococcus Chroococcus Bacteria as a Biocatalyst

Methane is an extensively accessible green energy that can be obtained organically just by way of through natural gases. However, using methane in fuel at ambient temperature conditions is quite challenging, due to its high thermodynamically stability. In this present investigation, the feasibility of using methane in the low-temperature microbial fuel-cell (MFC) with an unadulterated culture of Methylococcus chroococcus without the inclusion of any additional electron mediators is investigated. The microbial fuel cell setup was prepared using a salt bridge. Through potentiodynamic study, power density, and OCV, it can be seen that the setup delivers a sufficient amount of voltage and power as the days progress. Electrochemical Impedance Spectroscopic investigations also depict the fact that the cell required roughly one day to balance out, and kept working at full force for up to seven days. This work exhibits the chance of creating power utilizing methane as one of the main carbon sources at ambient temperature with an M. chroococcus unadulterated culture as the direct electron-transporting MFC biocatalyst.

Terminal π-group engineering of organic co-sensitizers for thiourea dye based dye-sensitized solar cells

To enhance the conversion efficiency of organic dye sensitized solar cells (DSSCs) via the co-sensitization strategy, a series of organic co-sensitizers (CS1–3) for thiourea dye D8 were designed and synthesized. They take carbazole as the donor unit and 2-cyanoacrylic acid as the anchoring group. Their π-bridges contain a thiophene primary spacer and a different terminal aromatic linker, i.e., thiophene, furan, and benzene for CS1–3, respectively. The effects of different terminal spacer group on the optical, electrochemical, and photovoltaic properties of carbazole-based co-sensitizers were investigated comprehensively. Moreover, the roles of CS1–3 as co-sensitizers for D8 are further examined. The co-sensitized cells based on D8 and CS3 exhibited the highest power conversion efficiency (PCE) of 8.53%, which was superior to that of devices with D8 (PCE = 7.92%). Theoretical calculation investigation revealed that CS3 incorporating a benzene terminal group possessed the most twisty configuration, which may be beneficial to the prevention of aggregation and electron recombination. Furthermore, incident photon to current efficiency (IPCE) spectra and electrochemical impedance spectroscopy (EIS) investigations were performed to clarify the mechanism of the co-sensitization behavior.

Isomeric tetrazole-based organic dyes for dye-sensitized solar cells: Structure-property relationships

Two new organic dyes (SD-1 and SD-2) featured with donor–π–acceptor architecture were synthesized and applied to dye-sensitized solar cells (DSSCs). In these sensitizers, an azo bridge π-spacer is used to link the phenyl tetrazole acceptor with 2-naphthol donors. To amplify the pull-push effect, the nitro group was connected to the electron acceptor group. The effect of the position of the nitro group and the tetrazole group linked to the benzene ring on the photophysical, electrochemical, and photovoltaic properties of sensitizers are investigated in detail. They all show intense UV–Vis absorptions around 400 nm and 510 nm. The co-sensitizations of SD-1 and SD-2 with ruthenium complex HD-2 are further evaluated and the co-sensitization results were compared with DCA. Co-sensitization of HD-2 with SD-2 was more efficient than found for co-sensitization with DCA (5.6% higher). Moreover, the influences of molecular geometry on charge recombination and photovoltaic performance of DSSCs were systematically investigated by incident photon to current efficiency (IPCE) spectra and electrochemical impedance spectroscopy (EIS) investigations.

Prussian blue based impedimetric urea biosensor

• Prussian blue (PB) based impedimetric urea biosensor was designed. • FTO was modified by Prussian blue and immobilized urease (glass/FTO/PB/urease biosensor). • Sensitivity of the glass/FTO/PB/urease biosensor is 2.55 Ω cm 2 mM −1 . • The glass/FTO/PB/urease biosensor exhibits linear range from 0.1 mM to 5.4 mM. • Acidic conditions improve PB stabilisation in ammonium ion containing medium. In this research an impedimetric urea biosensor was formed by modifying a fluorine doped tin oxide coated glass slide (glass/FTO) with a layer of PB (glass/FTO/PB), which was further stabilized in ammonium ion-containing medium, and immobilizing urease (glass/FTO/PB/urease) with vapor of glutaric aldehyde. Fast Fourier transform electrochemical impedance spectroscopy (FFT-EIS) investigation of the glass/FTO/PB/urease-based biosensor in urea-containing buffer solution indicated that the glass/FTO/PB/urease-based biosensor exhibits good sensitivity to urea (2.55 Ω cm 2 mM −1 ) and a range of linearly detectable concentrations of urea from 0.1 mM to 5.4 mM (R 2 = 0.992). To determine the optimal conditions of PB layer stabilisation, the influence of acidity of NH 4 Cl solution on the efficiency of cyclic voltammetry-based stabilization of PB layer was investigated in this research as well.

Mechanism investigation of PtPd decorated Zn0.5Cd0.5S nanorods with efficient photocatalytic hydrogen production combining with kinetics and thermodynamics

Different components of PtPd bimetallic cocatalysts modified Zn0.5Cd0.5S nanorods have already been designed and prepared in this study. The obtained hybrid photocatalysts were tested and characterized by XPS, ICP-OES and UV-Vis spectra, TEM and EDX tools. Such characterizations can prove the formation of PtPd bimetallic alloy particles in hybrid catalysts. Under visible light illumination, an outstanding hydrogen producing rate of 9.689 mmol·g−1·h−1 and a high AQY efficiency up to 10.43% at 420 nm are achieved in this work. In addition, thermodynamics (DFT calculations) and kinetics (Photoluminescence emission, photocurrent responses, electrochemical impedance spectroscopy and surface photovoltage spectra) investigations illustrate that PtPd bimetallic alloy has similar catalytic thermodynamic properties to Pt, which can greatly boost the charge separation and speed up the charge transfer, and decrease the activation energy of H2 generation. Notably, the calculation data suggests that Pt is thermodynamically favorable, while PtPd alloy is kinetically beneficial to H2 production, which can be ascribed to the higher activity of PtPd/Zn0.5Cd0.5S than Pt/Zn0.5Cd0.5S. This work can propose a fresh perspective for preparing high efficiency hybrid photocatalysts.

Corrosion Behavior of Al0.1CoCrFeNi High Entropy Alloy in Various Chloride-Containing Solutions

The present work investigates the corrosion behavior of Al0.1CoCrFeNi high entropy alloy (HEA) in various concentrations of chloride-containing solutions. Electrochemical tests exhibit overall excellent corrosion resistance of this alloy against the attack of Cl−-containing solutions. The main type of corrosion topography presents an intergranular feature. In addition, electrochemical impedance spectroscopy (EIS) investigation of the HEA samples under immersion test suggests chloride anion–containing environment leads to the decline of passivation film quality. Further analysis of XPS results reveals that significant amounts of elements exist with atomic states in the passive films.

Directionality of thermal gradients in lithium-ion batteries dictates diverging degradation modes

Intentionally applied interelectrode thermal gradients (ITGs) accelerate capacity loss in 35°C cells, and the directionality of the thermal gradient dictates the responsible degradation mode. By simulating cell self-heating at various temperatures and C-rates, we identify 35°C and C/5 as a condition that does not typically exhibit lithium (Li) plating under isothermal conditions but is sensitive to thermal gradients. When subjected to an ITG, we observe 77% capacity fade over 20 cycles when the negative electrode (NE) is warmer than the positive electrode (PE) (ΔTint = +2°C) and 100% capacity fade when the PE is warmer than the NE (ΔTint = −2°C). Incremental capacity analysis diagnoses PE degradation for ΔTint = +2°C and NE degradation for ΔTint = −2°C. Electrochemical impedance spectroscopy and postmortem optical investigation corroborate these findings. We identify ITGs as a means to achieve accelerated aging of Li-ion cells with the capability to dictate a limiting electrode and/or decouple degradation of each electrode.

How the Morphology of Nafion-Based Membranes Affects Proton Transport.

This work represents a systematic and in-depth study of how Nafion 1100 membrane preparation procedures affect both the morphology of the polymeric film and the proton transport properties of the electrolyte. The membrane preparation procedure has non-negligible consequences on the performance of the proton-exchange membrane fuel cells (PEMFC) that operate within a wide temperature range (up to 120 °C). A comparison between commercial membranes (Nafion 117 and Nafion 212) and Nafion membranes prepared by three different procedures, namely (a) Nafion-recast, (b) Nafion uncrystallized, and (c) Nafion 117-oriented, was conducted. Electrochemical Impedance Spectroscopy (EIS) and Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) investigations indicated that an anisotropic morphology could be achieved when a Nafion 117 membrane was forced to expand between two fixed and nondeformable surfaces. This anisotropy increased from ~20% in the commercial membrane up to 106% in the pressed membrane, where the ionic clusters were averagely oriented (Nafion 117-oriented) parallel to the surface, leading to a strong directionality in proton transport. Among the membranes obtained by solution-cast, which generally exhibited isotropic proton transport behavior, the Nafion uncrystallized membrane showed the lowest water diffusion coefficients and conductivities, highlighting the correlation between low crystallinity and a more branched and tortuous structure of hydrophilic channels. Finally, the dynamic mechanical analysis (DMA) tests demonstrated the poor elastic modulus for both uncrystallized and oriented membranes, which should be avoided in high-temperature fuel cells.

Preparation and study of photocatalytic performance of a novel Z-scheme heterostructured SnS2/BaTiO3 composite

SnS2 was hybridized with BaTiO3 to form an efficient and cheap Z-scheme heterojuncted SnS2/BaTiO3 photocatalyst by depositing nanosized SnS2 on the surface of commercial micro-sized BaTiO3. Multiple characterization techniques have been employed to study the as-prepared samples. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) results reveal that SnS2 partly covers BaTiO3. The photoluminescence (PL) spectra and the electrochemical impedance spectroscopy (EIS) investigation exhibit that the heterojunction SnS2/BaTiO3 has improved the separation and transfer of the photogenerated electron-hole pairs. UV–Vis-DRS and Mott-Schottky measurement give the estimated Eg, ECB, and corresponding calculated EVB, which meet the requirements of Z-scheme. The photocatalytic efficiency (degradation is 98% within 20 min) has been greatly enhanced much higher than pure SnS2. Free radical trapping experiments indicates that superoxide (•O2−) is the dominant active species of the reaction system. The improved photocatalytic performance, as well as the free radical trapping experiments support the Z-scheme mechanism for composite photocatalyst SnS2/BaTiO3. This work reveals that Z-scheme composite SnS2/BaTiO3 has prospect in treating organic pollution in waste water.

In-situ electrochemical impedance spectroscopy investigations on the early stage corrosion behavior of Zircaloy-4 in high-temperature lithiated water

The corrosion behavior of Zircaloy-4 (Zry-4) at 360 °C 0.01 M LiOH aqueous solution was in-situ monitored by electrochemical impedance spectroscopy (EIS). The EIS spectra of the as-received Zry-4 (Zry-4A) shows two-time constants feature during corrosion. The oxide layer impedance and capacitive show cyclic behavior while those of β-quenched Zry-4 sample (Zry-4Q) increased with exposure time increases. It may relate to the evolution of the defects and dielectric property of the oxide film and relaxation which evolves after the stress relief. The effect of heat treatment on the corrosion mechanism of the Zircaloy-4 was discussed.

EIS Investigation on the Influence of Natural Releasing of Inhibitor from Coral Aggregate on the Steel Corrosion in Coral Aggregate Concrete

Abstract Steel corrosion in coral aggregate concrete (CAC) mixed with different inhibitors was investigated using electrochemical impedance spectroscopy (EIS) technique in this paper. Considering the porosity characteristic of coral aggregate, a novel method of premixing inhibitor into coral aggregate was proposed and compared with the conventional mixing method for inhibitor. Three equivalent circuits were proposed and validated for the interpretation of EIS data of CAC. Finally, the influences of inhibitor type (calcium nitrite [CN] and amino-alcohol [AA] inhibitor), inhibitor content, and mixing method on the steel corrosion in CAC were analyzed and discussed through the EIS results. Results indicated that there were good fitting effects for the proposed circuits fitting the EIS data of steel in CAC mixed with different inhibitors. The anticorrosion effect of 3 % CN inhibitor is better than that of 2 % AA inhibitor in early phase (0–180 days), whereas the effect of the latter is more pronounced than the former in late period (180~270 days). In addition, according to the evolution of passive film resistance of steel in CAC, the premixing method is proven to be more effective than the direct-mixing method in long-term anticorrosion work. Finally, a unified equivalent circuit was established to interpret the EIS data of CAC, which has a promising significance in the further investigation of steel corrosion in CAC.

Studies on Dynamic Properties of Ultracapacitors Using Infinite r–C Chain Equivalent Circuit and Reverse Fourier Transform

The specific power storage capabilities of double-layer ultracapacitors are receiving significant attention from engineers and scientific researchers. Nevertheless, their dynamic behavior should be studied to improve the performance and for efficient applications in electrical devices. This article presents an infinite resistor–capacitor (r–C) chain-based mathematical model for the analysis of double layer ultracapacitors. The internal resistance and capacitance were measured for repetitive charging and discharging cycles. The magnitudes of internal resistance and capacitance showed approximately ±10% changes for charge-discharge processes. Electrochemical impedance spectroscopy investigations revealed that the impedance of a double-layer ultracapacitor does not change significantly in the temperature range of (−30 °C to +30 °C) and voltage range of (0.3376–2.736 V). The analysis of impedance data using the proposed mathematical model showed good agreement between the experimental and theoretical data. The dynamic behavior of the ultracapacitor was successfully represented by utilizing the proposed infinite r–C chains equivalent circuit, and the reverse Fourier transform analysis. The r–C electrical equivalent circuit was also analyzed using the PSIM simulation software to study the dynamic behavior of ultracapacitor parameters. The simulation study yields an excellent agreement between the experimental and calculated voltage characteristics for repetitive charging-discharging processes.

Cathode Performance Study of La0.6Sr0.4Co0.8Fe0.2O3-δ with Various Electrolyte-Doped Ceria Ce0.8Sm0.17Ln0.03O1.9 for IT-Solid Oxide Fuel Cell

La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF) cathode perovskite prepared by a Pechini method deposited on ceria co-doping Ce0.8Sm0.17Ln0.03O1.9 (LnSDC), with (Ln = La, Y, and Nd) electrolytes was successfully prepared by the solid-state reaction method. In this preparation process, thick and thin films of LSCF were deposited upon dense Ln-doped ceria LnSDC electrolytes after 5 and 3 spin-coating and dip-coating cycles, respectively. Two layers of LSCF were deposited by screen-printing in order to obtain thick cathode films. After deposition, some structural and morphologic characterizations, such as X-ray diffraction analysis and scanning electron microscopy, have been conducted to understand the properties of the elaborated samples and to study the impact of doping on these properties. Electrochemical impedance spectroscopy measurements on symmetric cells were also performed to investigate the employability of L0.6Sr0.4Co0.8Fe0.2O3-δ as a cathode material deposited upon LnSDC electrolytes for intermediate-temperature solid oxide fuel cells (IT-SOFC). According to what was available and inferred after studying the images from a scanning electron microscope, no cracks or significant segregation were detected in the LSCF/LnSDC interface. This behavior is consistent with the good thermal expansion compatibility between the two materials. Electrochemical impedance spectroscopy investigations at 700°C, indicate relatively low area-specific resistance between 0.048 and 0.1 Ω cm2 for all symmetrical cell LSCF/doped electrolyte/LSCF. All the cells were previously sintered above 1400°C, in air. All these results showed that L0.6Sr0.4Co0.8Fe0.2O3- δ can stand as a potential candidate for new cathode material in IT-SOFCs.

Three dimensional YSZ interface engineering layer for enhancement of oxygen reduction reactions of low temperature solid oxide fuel cells

In this study, we fabricated three dimensional yttria-stabilized zirconia (YSZ) interface engineering layer (IEL) by using a DC sputtering method to enhance oxygen reduction reactions (ORRs) of low temperature solid oxide fuel cells (LT-SOFCs). In order to deposit three dimensional YSZ IEL, a commercial Y–Zr metal alloy target was sputtered under various deposition pressure conditions (4, 8, 12 Pa) and then annealed at 800 °C for 6 h. Phase transformation of metal alloy Y–Zr to YSZ was identified by X-ray diffraction, X-ray photoelectron spectroscopy and high resolution-transmission electron microscope. The roughness of the three dimensional YSZ IELs were strongly related to the deposition pressure of the sputtering technique. After physical and chemical characterization, electrochemical examinations proved that the three dimensional YSZ IELs efficiently improved the ORR activity by geometrical effects. The fuel cell with the IEL fabricated at 8 Pa condition achieved the best power density (37.9 mW/cm2), which was 30.2% improved performance compared to the fuel cell without IEL (29.1 mW/cm2). Electrochemical impedance spectroscopy investigations also proved that rough three dimensional YSZ IELs efficiently enhance the performance of LT-SOFCs.

New organic dyes with varied arylamine donors as effective co-sensitizers for ruthenium complex N719 in dye sensitized solar cells

Three new organic dyes (TD1–TD3) featured with donor–π–acceptor architecture are synthesized and applied to dye-sensitized solar cells (DSSCs). In these sensitizers, an alkyl oligothiophene π-spacer is used to link the 2-cyanoacrylic acid acceptor with varied arylamines donors, i.e. carbazole (TD1), phenothiazine (TD2) or triphenylamine (TD3). The effects of different donor units on the photophysical, electrochemical, and photovoltaic properties of sensitizers are investigated in detail. They all show intensive UV–vis absorption around 400 nm with rod-like molecular structures. The co-sensitizations of TD1–TD3 with ruthenium complex N719 are further evaluated. Consequently, the co-sensitized DSSCs demonstrate superior photovoltaic performances with power conversion efficiencies (PCEs) ranging from 7.60% to 8.02% in relation to the cell with N719 (PCE = 7.29%) alone, which is mainly ascribed to the higher short-circuit photocurrents (Jsc) in combination with larger open-circuit voltages (Voc). Moreover, the origins of these improvements are examined by incident photon to current efficiency (IPCE) spectra and electrochemical impedance spectroscopy (EIS) investigations. The Jsc is improved because TD1–TD3 could compensate for the photocurrent loss induced by I−/I3−; whereas, the Voc is enhanced owing to the fact that the electron recombination process is retarded upon co-sensitization.