Search Results (26)

Electrochromic supercapacitors (ECSCs), which visually indicate their operating status through color changes, have attracted considerable attention in the field of wearable electronics. The conductive polymer polyaniline (PANI) shows great potential for integrated intelligent devices by combining bi-functional electrochromic spectral modulation and energy storage capabilities. In this work, a microsphere-like structured PANI-based composite film was fabricated on a porous Au/nylon 66 electrode via a one-step electrochemical copolymerization process, using 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PTSA) as both the dopant and cross-linking agent for the PANI backbone, serving as the ECSC electrode. Compared to the pristine PANI electrode, the PANI-PTSA composite film exhibits lower intrinsic resistance and higher electrical conductivity, delivering a higher specific capacitance of 310.0 F g⁻¹@1 A g⁻¹ and an areal capacitance of 340.0 mF cm⁻²@1 mA cm⁻², respectively. The dopant facilitates enhanced electrochemical performance by promoting charge transport within the PANI polymer network. Meanwhile, as a counter anion to the PANI backbone, PTSA regulates the growth of PANI chains and acts as a morphological controller. Furthermore, a symmetric ECSC based on the PANI-PTSA_8:1 electrode was assembled, and its electrochemical properties were thoroughly investigated. The device demonstrated a high specific capacitance of 169.2 mF cm⁻² at 1 mA cm⁻², a notable energy density of 23.5 μWh cm⁻² at a power density of 0.5 mW cm⁻², and excellent cycling stability with 79% capacitance retention after 3000 cycles at a current density of 5 mA cm⁻², alongside remarkable mechanical flexibility. Additionally, the working status of the ECSCs can be directly monitored through reversible color changes from yellow-green to deep blue during charge–discharge processes. Full article

In this work, a promising material of polyaniline (PANI) and two-dimensional molybdenum diselenides consisting of a PANI@2D-MoSe₂ binary composite was prepared by an electrochemical polymerization ethod. The as-prepared PANI@2D-MoSe₂, the polymer covered in the sheet-like structure of 2D-MoSe₂ surface morphologies, was observed through FE-SEM and HR-TEM studies. The SAED pattern of PANI@2D-MoSe₂ was observed to be in an octahedral phase. The octahedral crystalline phase was also confirmed based on the XRD pattern. In addition, EIS studies of the PANI@2D-MoSe₂ binary composite counter electrode (CE) revealed the highest electrical conductivity of 3.47 × 10⁻⁴ S/cm at room temperature. The DSSCs assembled the PANI@2D-MoSe₂ CE, which amounted to a 7.38% efficiency. Pristine PANI, 2D-MoSe₂, and Pt CEs exhibited efficiencies of 5.07%, 5.82%, and 6.61%. The PANI integrated with 2D (MoSe) combines influences of conductivity and stability for future energy conversion technologies. Full article

The pursuit of sustainable energy sources has led to significant advances in solar cell technology, with conducting polymers (CPs) emerging as key innovations. This review examines how CPs improve the performance and versatility of three important types of solar cells: dye-sensitized solar cells (DSSCs), perovskite solar cells (PSCs), and organic solar cells (OSCs). Polymers such as polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene) have shown significant potential to increase the efficiency of solar cells. In DSSCs, conducting polymers act as counter electrodes, electrolytes, and dyes, contributing to improved efficiency and stability. In PSCs, they serve as hole transport materials and electron transport materials that improve charge separation and reduce recombination losses. In OSCs, conducting polymers act as HTMs and active layers, significantly impacting device performance and enabling advances in both binary and ternary solar cell configurations. Recent research highlights the important role of conducting polymers in improving both the efficiency and stability of solar cells under different indoor and outdoor lighting conditions. Recent advances have led to impressive energy conversion efficiencies, particularly in low-light environments. This report also highlights the environmental and economic benefits associated with these materials. At the same time, it highlights the challenges associated with optimizing the materials, scalability, and ensuring long-term stability. Future research directions are outlined to overcome these obstacles and promote the commercial viability of next-generation solar technologies. Full article

Conducting polymers are emerging as promising alternatives to rare and expensive platinum for counter electrodes in dye-sensitized solar cells; due to their ease of synthesis, they can be chemically tuned and are suitable for roll-to-roll production. Among these, poly (3,4-ethylenedioxythiophene) (PEDOT)-based counter electrodes have shown leading photovoltaic performance. However, certain conductivity issues remain that affect the effectiveness of these counter electrodes. In this study, we present an electropolymerized PEDOT and poly(N-alkylated-carbazole) copolymer as an efficient electrocatalyst for the reduction in ${\mathrm{I}}_3^{-}$ in dye-sensitized solar cells. Copolymerization with N-alkylated carbazoles significantly increases the conductivity of the polymer film and facilitates rapid charge transport at the interface between the polymer electrode and the electrolyte. The length of the alkyl substituents also plays a crucial role in this improvement. Electrochemical analysis showed a reduction in charge transport resistance from 3.31 Ω·cm² for PEDOT to 2.26 Ω·cm² for the PEDOT:poly(N-octylcarbazole) copolymer, which is almost half the resistance of a platinum-based counter electrode (4.12 Ω·cm²). Photovoltaic measurements showed that the solar cell with the PEDOT:poly(N-octylcarbazole) counter electrode achieved an efficiency of 8.88%, outperforming both PEDOT (7.90%) and platinum-based devices (7.57%). Full article

Dye-sensitized solar cells with synthesized phenothiazine derivative 3,7′-bis(2-cyano-1-acrylic acid)-10-ethyl-phenothiazine (PTZ) and commercial di-tetrabutylammonium cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II) (N719) dyes were fabricated and characterized based on current–voltage measurements. The effect of the utilization of individual dyes and its mixture, chenodeoxycholic acid as co-adsorbent addition, replacement of I⁻/I₃⁻ by Co^2+/3+ ions in electrolyte and platinum by semiconducting polymer mixture poly(3,4-ethylenedioxythiophene) polystyrene sulfonate in counter electrode was studied. Additionally, the effect of polymer thickness on the photovoltaic performance of the device was evaluated. Prepared photoanodes were characterized by UV–Vis spectroscopy and atomic force microscopy. The further modification of DSSCs involving the fabrication of tandem solar cells was carried out. The higher power conversion efficiency 7.60% exhibited tandem photovoltaic cell sensitized with dyes mixture containing co-adsorbent, I⁻/I₃⁻ ions in the electrolyte, and platinum in the electrode. Full article

In dye-sensitized solar cells (DSSCs), the counter electrode (CE) plays a crucial role as an electron transfer agent and regenerator of the redox couple. Unlike conventional CEs that are generally made of glass-based substrates (e.g., FTO/glass), polymer substrates appear to be emerging candidates, owing to their intrinsic properties of lightweight, high durability, and low cost. Despite great promise, current manufacturing methods of CEs on polymeric substrates suffer from serious limitations, including low conductivity, scalability, process complexity, and the need for dedicated vacuum equipment. In the present study, we employ and evaluate a fully additive manufacturing route that can enable the fabrication of CEs for DSSCs in a high-throughput and eco-friendly manner with improved performance. The proposed approach sequentially comprises: (1) material extrusion 3-D printing of polymer substrate; (2) conductive surface metallization through cold spray particle deposition; and (3) over-coating of a thin-layer catalyzer with a graphite pencil. The fabricated electrodes are characterized in terms of microstructure, electrical conductivity, and photo-conversion efficiency. Owing to its promising electrical conductivity (8.5 × 10⁴ S·m⁻¹) and micro-rough surface structure (R_a ≈ 6.32 µm), the DSSCs with the additively manufactured CEs led to ≈2.5-times-higher photo-conversion efficiency than that of traditional CEs made of FTO/glass. The results of the study suggest that the proposed additive manufacturing approach can advance the field of DSSCs by addressing the limitations of conventional CE manufacturing platforms. Full article

Recent progress concerning the development of counter electrode material (CE) from the dye-sensitized solar cells (DSSCs) and the electrode material (EM) within supercapacitors is reviewed. From composites based on carbon nanotubes (CNTs) and conducting polymers (CPs) to their biggest competitor, namely composites based on graphene or graphene derivate (GD) and CPs, there are many methods of synthesis that influence the morphology and the functionalization inside the composite, making them valuable candidates for EM both inside DSSCs and in supercapacitors devices. From the combination of CPs with carbon-based materials, such as CNT and graphene or GD, the perfect network is created, and so the charge transfer takes place faster and more easily. Inside composites, between the functional groups of the components, different functionalizations are formed, namely covalent or non-covalent, which further provide the so-called synergic effect. Inside CPs/CNTs, CNTs could play the role of template but could also be wrapped in a CP film due to π–π coupling enhancing the composite conductivity. Active in regenerating the redox couple I⁻/I₃⁻, the weakly bound electrons play a key role inside CPs/GD composites. Full article

The metallo-supramolecular polymer (MSP) is considered one of the most promising electrodes for electrochromic devices due to its intrinsically stable redox properties. Nevertheless, despite extensive work focusing on improving the electrochromic and electrochemical properties of MSPs, little experimental evidence exists from in-depth investigations on the anion-induced electrochromism of MSPs. Herein, Ru-based metallo-supramolecular polymer (polyRu) films with excellent electrochromic performance were fabricated through a novel electrochemical deposition method, and the electrochromic mechanism was further understood. The polyRu films possess fast reaction kinetics with a short switching time of 4.0 s (colored) and 2.8 s (bleached) and highly reversible redox properties due to the resulting impacts on the capacitive behaviors (containing surface, near-surface and intercalation pseudo-capacitance) of the perchlorate ions in the electrochromic process. Moreover, the electrochromic degradation of the polyRu films is considered to stem from the numerous nanopores in the film induced by ClO₄⁻ transport and the exchange of counter anions from Cl⁻ to ClO₄⁻. In addition, a physical model, revealing the transport of conduction ions and the evolution of the structure and properties of the polyRu film during the electrochromic process, is presented. It is observed that the charge balance of Ru³⁺ and Ru²⁺, achieved through the adsorption/desorption of ClO₄⁻ on the film, provides electrochromic and electrochemical reversibility to the polyRu film under positive/negative bias. Correspondingly, a transformation from polyRu·(Cl⁻)_2n to polyRu·(ClO₄⁻)_x(Cl⁻)_2n−x in the polyRu film is induced by a counter anion exchange from Cl⁻ to ClO₄⁻. Revealing the detailed perchlorate ion transfer kinetics and electrochromic mechanism in this film can offer new insights into the application of metallo-supramolecular polymers in electrochromic devices. Full article

In recent decades, significant research efforts have been devoted to studying various types of actuators. Of particular interest are soft actuators based on electroactive polymers, which offer low operating voltage, light weight, and fast response. In this study, we demonstrate the feasibility of a soft linear actuator fabricated from polypyrrole (PPy), an electroactive polymer that is easy to synthesize, cost-effective, and biocompatible. By optimizing the polymerization conditions, the operation condition and environment, we were able to achieve improved and stable actuator performance. Furthermore, we developed a new actuator-contained component with a flexible counter electrode to build an actuator that operates in air. This approach enabled us to build small and lightweight actuators that operate in air, with a diameter of 5 mm, resembling artificial muscles. Our resulting miniaturized and integrated linear PPy-based actuators can be driven at low voltages (±1.5 V), making them suitable for use in various parts of the body. As such, this actuator holds significant potential for a wide range of applications in the fields of soft electronics, drug delivery, artificial organs, and muscles, as well as a component material for portable medical sensors and devices. Full article

Electrochemical energy storage systems have a wide range of commercial applications. They keep energy and power even at temperatures up to +60 °C. However, the capacity and power of such energy storage systems reduce sharply at negative temperatures due to the difficulty of counterion injection into the electrode material. The application of organic electrode materials based on salen-type polymers is a prospective approach to the development of materials for low-temperature energy sources. Poly[Ni(CH₃Salen)]–based electrode materials synthesized from different electrolytes were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and quartz crystal microgravimetry at temperatures from −40 °C to 20 °C. By analyzing data obtained in various electrolyte solutions, it was shown that at subzero temperatures, the process of injection into the polymer film, together with slow diffusion within the film, predominantly limit the electrochemical performance of electrode materials based on poly[Ni(CH₃Salen)]. It was shown that the deposition of the polymer from solutions with larger cations allow the enhancement of the charge transfer due to the formation of porous structures facilitating the counter-ion diffusion. Full article

Over the past few decades, electrochromism has been a prominent topic in energy-saving applications, which is based on the mechanism of altering the optical transmittance of EC materials under the effect of a small applied voltage. Thus, tungsten oxide (WO₃) is a significant chemical compound typically applied in electrochromic devices (ECDs) as it is responsible for the optical transmittance variation. In this work, the WO₃ films were produced through a sol–gel spin-coating method. The effect of various transparent conducting oxides (TCOs, which are indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO) glass substrates, and aluminum-doped zinc oxide (AZO)) was investigated in the construction of ECDs. Based on a conducting polymer polypyrene carbonate electrolyte, ITO and aluminum-doped zinc oxide (AZO)-coated glasses were also examined as counter electrodes. The electrode combination employing FTO and ITO as the TCO and counter electrode, respectively, exhibited the most significant coloration efficiency of 72.53 cm²/C. It had coloring and bleaching transmittance of 14% and 56%, respectively, with a large optical modulation of 42%. In addition to that, ECDs with the AZO counter electrode have the advantage of lower intercalation charges compared to ITO and FTO. Hence, this research offers a new avenue for understanding the role of common TCO and counter electrodes in the development of WO₃-based ECDs with conducting polymer electrolytes. Full article

Antibiotics are increasingly used to treat certain bacteria that are harmful to humans. However, their inadequate or excessive use can lead to the proliferation of certain more resistant strains, which ultimately reduces their effectiveness. To counter this, it is essential to limit the amount of antibiotics ingested, particularly through animal food, if the animals themselves have received antibiotic treatment. In the case of milk, it is necessary to be able to detect quantities of antibiotics in the range of a few parts per billion. A sensor has therefore been developed for this purpose. The sensitive layer that we propose to use in this study, is based on a molecularly imprinted conductive polymer (MICP) that allows a very specific interaction and have been integrated into electrochemical detection approaches by polymerization on electrodes. The sensor is based on the measurement of the variation in conductivity of a sensitive layer deposited between two electrodes, which is influenced by the presence of the antibiotic. Although it seems possible to further improve the performance of these sensors, their use in this field seems very promising considering the obtained results. Full article

In this work, the quasi-solid-state polymer electrolyte containing poly(vinyl alcohol)-polypyrrole as a polymer host, potassium iodide (KI), iodine (I₂), and different plasticizers (EC, PC, GBL, and DBP) was successfully prepared via the solution casting technique. Fourier transform infrared spectroscopy (FTIR) was used to analyze the interaction between the polymer and the plasticizer. X-ray diffraction confirmed the reduction of crystallinity in the polymer electrolyte by plasticizer doping. The ethylene carbonate-based polymer electrolyte showed maximum electrical conductivity of 0.496 S cm⁻¹. The lowest activation energy of 0.863 kJ mol⁻¹ was obtained for the EC-doped polymer electrolyte. The lowest charge transfer resistance R_ct1 was due to a faster charge transfer at the counter electrode/electrolyte interface. The polymer electrolyte containing the EC plasticizer exhibited an average roughness of 23.918 nm. A photo-conversion efficiency of 4.19% was recorded in the DSSC with the EC-doped polymer electrolyte under the illumination of 100 mWcm⁻². Full article

Electroactive polymers (EAPs), especially dielectric elastomer actuators (DEAs), belong to a very promising and emerging class of functional materials. While DEAs are mostly utilized to rely on carbon-based electrodes, there are certain shortcomings of the use of carbon electrodes in the field of soft robotics. In this work we present a fish-like bending structure to serve as possible propulsion element, completely avoiding carbon-based electrodes. The presented robot is moving under water, using a particularly tailored conductive hydrogel as inner electrode and a highly anisotropic textile material to manipulate the bending behavior of the robot. The charge separation to drive two DEAs on the outsides of the robot is provided by the conductive hydrogel while the surrounding water serves as counter electrode. To characterize the hydrogel, tensile tests and impedance spectroscopy are used as measurement methods of choice. The performance of the robot was evaluated using a digital image correlation (DIC) measurement for its bending deflections under water. The developed fish-like robot was able to perform a dynamic bending movement, based on a tri-stable actuator setup. The performed measurements underpin the sufficient characteristics for an underwater application of conductive hydrogel electrodes as well as the applicability of the robotic concept for under water actuations. Full article

In this study, polymer-assisted dispersants are used to stabilize the nanohybrids of platinum nanoparticles (PtNPs)/carbon nanotubes (CNTs) through non-covalent bond forces. These dispersants aim to replace the florine-doped tin oxide (FTO) glass in traditional dye-sensitized solar cells (DSSCs) as counter electrodes. The large specific surface area, high conductivity, and redox potential of PtNPs/CNT nanohybrids are used as the basis to utilize them as the counter electrode material to fabricate a dye-sensitized solar cell. The conductivity results indicate that the resistance of the PtNP/CNT nanohybrid film can be reduced to 7.25 Ω/sq. When carbon nanotubes are mixed with platinum nanoparticles at a weight ratio of 5/1, the photoelectric conversion efficiency of DSSCs can reach 6.28%. When using the FTO-containing substrate as the counter electrode, its conversion efficiency indicates that the micro-/nano-hybrid material formed by PtNPs/CNTs also exhibits an excellent photoelectric conversion efficiency (8.45%) on the traditional FTO substrate. Further, a large-area dye-sensitive cell is fabricated, showing that an 8 cm × 8 cm cell has a conversion efficiency of 7.95%. Therefore, the traditional Pt counter electrode can be replaced with a PtNP/CNT nanohybrid film, which both provides dye-sensitive cells with a high photoelectric conversion efficiency and reduces costs. Full article