[en] Highlights: • The low-potential polymerization of 2-(thiophen-2-yl)furan into polymer (PTFu) was reported. • The electrochemical performance of PTFu was studied in three different electrolytes. • The specific capacitance of PTFu electrode reached 392.0 F g"−"1 at 5 A g"−"1 and had 67.0% retention after 500 cycles. • The addition of boron trifluoride diethyl etherate into acetonitrile electrolyte benefited to enhance the specific capacitance and stability of PTFu electrode. - ABSTRACT: In this study, a new simple hybrid poly(2-(thiophen-2-yl)furan) (PTFu) was easily electrodeposited by direct anodic oxidation of 2-(thiophen-2-yl)furan in acetonitrile solution containing 0.1 M lithium perchlorate (LiClO_4). The oxidation onset potential of 2-(thiophen-2-yl)furan monomer in this medium was measured to be 0.90 V, which was lower than those of thiophene (1.47 V) and furan (1.28 V). The structure and morphology of PTFu were characterized by Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermal analysis. The electrochemical capacitance properties of PTFu electrode in three electrolytes were also investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscope techniques. The electrochemical results showed that the specific capacitance of PTFu electrode was enhanced to 392.0 F g"−"1 from 249.4 F g"−"1 at 5 A g"−"1 and the cycling stability was also enhanced to 67.0% retention from 25.5% retention after 500 cycles when the equivalent boron trifluoride diethyl etherate (BFEE) was added into the acetonitrile electrolyte. Furthermore, the PTFu electrode in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF_6) showed a lower specific capacitance value (209.4 F g"−"1 at 5 A g"−"1) and an improved stability (67.6% retention after 600 cycles). These results indicated that the conducting polymers based on furan should be a promising electrode material for supercapacitor applications when the electrolyte based-BFEE is used

[en] Graphical abstract: - Highlights: • Furan-EDOT monomers were synthesized using Stille coupling. • The electropolymerization of furan-EDOT monomers were reported. • Free-standing furan-EDOT films were electrosynthesized. • Furan-EDOT copolymers show enhanced redox activity and stability. • Furan-EDOT copolymers exhibits improved electrochromic performances. - Abstract: Most recently, conjugated oligo-/polymers containing furan have regained attention due to their unique properties and promising application in organic electronics. Herein, to acquire a thorough fundamental understanding of the electrosynthesis and properties of furan-EDOT copolymers from different initial monomers, the synthesis and electropolymerization performances of furan-EDOT monomers, namely 5-(furan-2-yl)-2,3-dihydrothieno[3,4-b][1,4]dioxin (EDOT-Fu), 5,7-di(furan-2-yl)-2,3-dihydrothieno[3,4-b][1,4]dioxin (Fu-EDOT-Fu), and 2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)furan (EDOT-Fu-EDOT), were comprehensively reported and the effect of different monomers on the structure and properties of the resulting polymers obtained under optimized electrical conditions were systematically evaluated. The monomers exhibit good blue-green photoluminescence with quantum yields ranging from 0.5 to 40%, which may be used as building blocks for rational design of fluorescent conjugated systems. The onset oxidation potential ranged from 0.78 V-0.45 V with the incorporation of EDOT unit in monomer chain, thus leading to the facile electrodeposition of free-standing films with improved optoelectronic properties in comparison with polyfuran. The obtained copolymers featured the advantageous combination of polyfuran and PEDOT, such as higher fluorescence and better planarity of polyfuran, transparency and excellent redox stability of PEDOT. Structure characterization and properties of the as-formed copolymer films from different initiative monomers, including FT-IR, UV-vis, TG, fluorescence, surface morphology and electrochromic properties, etc., were systematically investigated and comparatively discussed

[en] Graphical abstract: Electropolymerization of C4-EDOT-COOH and corresponding polymer's sensing application for environmental, pharmaceutical, biology and food. -- Highlights: •C4-EDOT-COOH monomer with good solubility in water was synthesized by an efficient five-step route. •That acidic conditions were favorable for the electropolymerization of C4-EDOT-COOH. •The resulting high-quality polymer film can be employed for the fabrication of chemo/bio-sensors and optical sensors. •These as-prepared sensors can be applied to the simple, fast and sensitive detection of different analytes. -- Abstract: Various electrochemical chemo/bio-sensors and optical sensors are facilely explored for the sensitive determination of biomolecules, drug molecules, environmental pollutants, and metal ions using a carboxylic-functionalized poly(3,4-ethylenedioxythiophene) derivative (PC4), which is easily obtained by the direct electropolymerization of a water-soluble 4-((2,3-dihydrothieno[3,4-b][1,4] dioxin-2-yl) methoxy)-4-oxobutanoic acid (C4-EDOT-COOH) monomer in a microemulsion system. The effect of different pH values on the electropolymerization of C4-EDOT-COOH monomer is investigated, and the as-prepared PC4 film is characterized by electrochemical method, infrared spectrum, and scanning electron microscope. The resulting high-quality PC4 film as a sensing material not only can combine with various biologically active species via covalent linkage and inorganic materials via layer-by-layer self-assembly for the construction of electrochemical chemo/bio-sensors, but also excellent optical performance of PC4 can be employed for the fabrication of optical sensors. These as-prepared chemo/bio-sensors can be applied to the simple, fast and sensitive detection of environmental pollutants, pharmaceuticals, hazardous substances, and biological active substance and nutrients present in food by means of electrochemistry, ultraviolet and fluorescence spectroscopy. Satisfactory results indicate that chemo/bio-sensors based on PC4 possess excellent chemo/bio sensing performance and enhanced optical response, and its carboxylic group can realize the immobilization of biologically active species, self-assembly of inorganic nanomaterials

[en] Preparing quantum dots (QDs) with strong stability against salts is extremely important in some environments with ultrahigh salts concentration, such as the oil exploitation, wastewater treatment and biological markers. In this paper, we reported a simple new method to prepared highly stable QDs by using multi-branched ligands. Our results suggested that multi-branched ligands-capped QDs have extremely good dynamic stability even in salt-saturated solution. Unlike to traditional dynamic stability theory, which considers the electrostatic repulsion of QDs dominant QD stability, the current work found a new determined factor: the steric hindrance of ligand structure. The high steric hindrance effect of multi-branched ligands can maintain the single dispersity of QDs even at extremely low electrostatic repulsion. As a result, QDs with ultrahigh stability against salts can be realized. (paper)

[en] Graphical abstract: The electrochemical capacitance performance of PEOTT electrode from water was comparatively investigated using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscope methods in the four solvent-electrolyte systems, i.e., H₂O–H₂SO₄, H₂O–HClO₄, H₂O–LiClO₄, and ACN–LiClO₄. The results revealed that the specific capacitance of PEOTT electrode was superior in acidic aqueous electrolytes than that in neutral pH aqueous or organic electrolyte. With these results, it is implied that PEOTT electrode employing HClO₄ aqueous electrolyte may be a promising electrode for supercapacitor applications. - Highlights: • A PEDOT sulfur analog was synthesized via chemical oxidation method firstly. • Effect of solvent on polymer structure was evaluated. • Effect of electrolyte on the capacitance performance was investigated. • PEOTT should be a promising supercapacitor material. - Abstract: Thieno[3,4-b]-1,4-oxathiane (EOTT), one asymmetrical analog of 3,4-ethylenedioxythiophene (EDOT), was synthesized and its chemical oxidative polymerization was carried out in different solvents (dichloromethane, water, and acetonitrile (CH₂Cl₂, H₂O, and ACN)). The effect of the solvent on the structure, crystalline characteristic, morphology, and thermal stability of poly(thieno[3,4-b]-1,4-oxathiane) (PEOTT) were investigated by fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetry, respectively. PEOTT prepared from H₂O exhibited higher electrical conductivity (∼10⁰ S/cm) and more robust thermal stability. The electrochemical capacitance performance of PEOTT electrode in ACN–LiClO₄ was initially found dissatisfactory. Furthermore, the electrochemical properties of this electrode in another three aqueous electrolytes (H₂SO₄, HClO₄, and LiClO₄) were also investigated comparatively by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS). It revealed the enhanced specific capacitance (208 F/g at 1 A/g) and improved capacitance retention (80.4% after 1000 cycles at 10 A/g) of PEOTT electrode in H₂O–HClO₄ compared to those of the electrode in ACN–LiClO₄. These results implied that PEOTT employing aqueous HClO₄ electrolyte should be a promising electrode material for supercapacitor applications.

[en] The development of asymmetric supercapacitors (ASCs) with high power and energy density is greatly restricted by the low capacitance of the anode materials. V₂O₅ is a promising anode material with high theoretical capacity, but its low conductivity and high dissolution are not conducive to applications in energy storage. Herein, oxygen-vacancy PEDOT/V₂O₅ ultrathin nanosheets with a thickness of about 4.4 nm are fabricated by the oxidative polymerization of EDOT monomers on V₂O₅ nanosheets in the absence of other oxidants. The results of XPS and EPR confirm that the polymerization of PEDOT increases the oxygen vacancy concentration of V₂O₅. The PEDOT/V₂O₅ nanosheets exhibit a specific capacitance of 406 F g^-1 at 2 mV s^-1 and excellent cyclic stability in the mixed organic electrolyte of dimethyl carbonate and ethylene carbonate. The energy density of ASCs composed of PEDOT/V₂O₅ as the anode and activated carbon as the cathode reaches 65 W h kg^-1 at a power density of 1490 W kg^-1. This means that PEDOT/V₂O₅ has enormous potential in high-energy storage. (authors)

[en] Single-walled carbon nanotubes (SWCNTs), PEDOT:PSS/SWCNTs, and SWCNTs/PEDOT:PSS nanofilms were used as working electrodes to electrodeposit polyaniline (PANI) in a mixed alcohol solution of isopropyl alcohol (IPA), boron trifluoride ethyl ether (BFEE), and polyethylene glycol (PEG). The thermoelectric (TE) performances of the resulting nanofilms were systematically investigated. SWCNTs/PEDOT:PSS/PANI nanofilms showed a relatively high electrical conductivity value of 232.0 S cm"−"1. The Seebeck coefficient was enhanced and exhibited the values of 33.8, 25.6, and 23.0 μV K"−"1 for the SWCNTs/PANI, PEDOT:PSS/SWCNTs/PANI, and SWCNTs/PEDOT:PSS/PANI films, respectively. The maximum power factor achieved was 12.3 μW m"−"1 K"−"2. This technique offers a facile and versatile approach to a class of layered nanostructures, and it may provide a general strategy for fabricating a new generation of conducting polymer/SWCNTs materials for further practical applications. (paper)

[en] Nowadays, inorganic/polymer composites have attracted significant interest in thermoelectric field, since the composite materials usually achieve their respective advantages complementary to each other. In this work, molybdenum diselenide (MoSe₂) was synthesized by a facile hydrothermal method. Solution processible two-dimensional (2D) MoSe₂ nanosheets (NSs) were successfully obtained using dimethylsulfoxide (DMSO) solvent or lithium intercalation procedure. Combined with Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), MoSe₂/PEDOT:PSS composite thin films were fabricated by direct vacuum-filtration method. Thermoelectric properties of composite thin films were investigated systematically and found that 2D MoSe₂ NSs and PEDOT:PSS have the synergistic effect on improving thermoelectric properties. The maximum power factor was calculated to be 48.6 µW m⁻¹ K⁻² with 5 wt% 2D MoSe₂ NSs embedding into PEDOT:PSS matrix, which is almost 69% higher than that of pure PEDOT:PSS. These results demonstrate that 2D inorganic/polymer composite method is one of promising strategies to get high-performance polymer-based thermoelectric composites. (paper)

[en] The wet-chemical approach is of great significance for the synthesis of two-dimensional (2D) bismuth telluride nanoplatelets as a potential thermoelectric (TE) material. Herein, we proposed a simple and effective solution method with the assistance of aniline for the fabrication of bismuth telluride nanoplatelets at a low temperature of 100 °C. The choice of aniline with its dual function avoided the simultaneous use of a capping regent and a toxic reductant. The as-synthesized nanoplatelets have a large size of more than 900 × 500 nm² and a small thickness of 15.4 nm. The growth of bismuth telluride nanoplatelets are related to the Bi/Te ratio of precursors indicating that a larger content of the Bi precursor is more conducive to the formation of 2D nanoplatelets. The bismuth telluride nanoplatelets pressed into a pellet show a smaller electrical resistivity (∼6.5 × 10⁻³ Ω · m) and a larger Seebeck coefficient (−135 μ V K⁻¹), as well as a lower thermal conductivity (0.27 W m⁻¹ K⁻¹) than those of nanoparticles. The next goal is to further reduce the electrical resistivity and optimize the TE performance by disposing of the residual reactant of aniline adsorbed on the surface of the nanoplatelets. (paper)

[en] A three-dimensional porous network graphene aerogel (GAs) with large specific area and excellent conductivity was loaded with β-cyclodextrin polymer (Pβ-CD) to serve as a support for immobilization of antibodies. A highly sensitive immunosensor for the cancer marker carbohydrate antigen 15–3 (CA15–3) was designed based on the use of Pβ-CD/GAs. The large specific area of GAs warrants high loading with antibodies, and their excellent electrical conductivity warrants strong electrical signals. Based on the synergistic effect of GAs and Pβ-CD, an immunoassay was designed that is making use of hexacyanoferrate as an electrochemical probe and having a pleasantly low working potential of 0.2 V (vs. SCE). Response is linear in the 0.1 mU mL⁻¹ to 100 U mL⁻¹ activity range, and the lower detection limit is 0.03 mU mL⁻¹ (at S/N = 3). The immunoassay is stable, selective and reproducible. It was applied to the analysis of spiked samples, and results were satisfactory. .