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Organic thermoelectric (TE) materials are regarded as the next‐generation TE materials because of their merits including low cost, high mechanical flexibility, and low intrinsic thermal conductivity. However, their Seebeck coefficient is usually quite low. Herein, a new strategy is demonstrated to greatly enhance the Seebeck coefficient of poly(3,4‐ethylenedioxy‐thiophene):poly(styrenesulfonate) (PEDOT:PSS), which is the most popular TE polymer, through polaron level splitting via π–π overlapping with nonpolar small aromatic molecules including anthracene, naphthalene, and pyrene. Although these aromatic molecules are neither oxidizing nor reducing agent, they can greatly enhance the Seebeck coefficient of PEDOT:PSS films pre‐treated with dimethyl sulfoxide, acid, or acid then base, while they do not lower the electrical conductivity too much. Through such a treatment with anthracene, the Seebeck coefficient can be up to 45.5 µV K−1, and the ZT value can be up to 0.27. The enhancement is ascribed to the splitting of the lower polaron energy level of PEDOT, which is induced by the π–π overlapping between the aromatic compounds and conjugated PEDOT. This can shift up the Fermi level, thereby enhancing the Seebeck coefficient. [ABSTRACT FROM AUTHOR]

Readily obtained highly conductive, transparent, and flexible poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films is urgently needed in printing of flexible transparent electrodes. A simple and facile method to enhance the electrical conductivity of PEDOT:PSS films is reported. The conductivity is increased by four orders of magnitude after adding solid chloroplatinic acid (H2PtCl6) into the pristine PEDOT:PSS solution. The H2PtCl6-doped PEDOT:PSS film exhibits a sheet resistance of 44 ± 5 Ω □-1 and a transmittance of 84 ± 1% at 550 nm, corresponding to a figure of merit of 47 ± 4. Comparative study shows addition of solid acid like H2PtCl6 is more effective in conductivity enhancement than addition of polar organic solvents, such as dimethyl sulfoxide or ethylene glycol. The mechanism for the conductivity enhancement is attributed to both in situ doping and phase separation of PEDOT:PSS. PEDOT is oxidized and doped by Pt4+ of H2PtCl6, which is reduced simultaneously to Pt2+. Proton transfer from H2PtCl6 to PSS− of PEDOT:PSS causes formation of neutral PSSH, leading to phase separation between insulating PSS and conducting PEDOT. Such a phase separation results in conformational changes of PEDOT chains and reduction in energy barrier for charge hopping. [ABSTRACT FROM AUTHOR]

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is the most successful conducting polymer in terms of practical application. It possesses many unique properties, such as good film forming ability by versatile fabrication techniques, superior optical transparency in visible light range, high electrical conductivity, intrinsically high work function and good physical and chemical stability in air. PEDOT:PSS has wide applications in energy conversion and storage devices. This review summarizes its applications in organic solar cells, dye-sensitized solar cells, supercapacitors, fuel cells, thermoelectric devices and stretchable devices. Approaches to enhance the material/device performances are highlighted. [ABSTRACT FROM AUTHOR]

[Display omitted] In recent years, the research on intrinsically safe aqueous zinc-ion batteries (AZIBs) has gained significant attention. However, the commercialization of AZIBs is hindered because of the formation of dendrites in them and undesired hydrogen evolution reaction (HER) at their anode. MXene is a promising two-dimensional material that can inhibit dendrite growth and undesired HER at the anode when used as a protective layer for the anode in AZIBs. MXene's surface functional groups play a crucial role in this protective function. However, the working mechanisms of these surface functional groups have not been thoroughly understood. Based on first-principles calculations and molecular dynamics simulation, we investigated the mechanisms of MXene with nine surface functional groups, including oxygen and halogen elements, as an anode protection layer. We checked their structural stability, electronic structure, adsorption energy, HER reaction free energy, Zn2+ diffusion energy barriers, coordination number of Zn2+- H 2 O and diffusion coefficients of Zn2+. The MXene species with -S and -O functional groups exhibit good electrical conductivity and greatly adsorb Zn2+. Conversely, MXene species with halogen-functional groups significantly inhibit HER reactions. MXene materials with -Se functional group have the best desolvation effect (ΔCN = 0.31), while those with -I end group have the fastest ability to diffuse zinc ion. This research provides a theoretical guidance for the design of MXene based anode protection layers, which can help to develop dendrite-free and low side-reaction AZIBs. [ABSTRACT FROM AUTHOR]

• A facile and cost-effective hydrothermal method was proposed to synthesize the Ni-doped MnO 2 bi-functional flexible electrode. • Bi-functional flexible electrode based on the heteroatom-doped MnO 2 electrode exhibits superior electrochemical performance. • Density functional theoretical calculation and electrochemical kinetic analysis are performed to investigate the effect of heteroatom doping on the electrode performance. As the fossil fuel consumption and energy shortage crisis worsen, it is urgent to develop multi-functional and cost-effective energy storage devices. However, the sluggish electrochemical kinetics of electrode materials is the major drawback which hinders their practical application. Herein, a heteroatom doped MnO 2 carbon-based flexible electrode has been proposed derived from Ni2+ doping α-MnO 2 by a facile hydrothermal strategy. Surprisingly, the as-prepared composite electrodes exhibit decent bi-functionally electrochemical performance both in lithium-ion batteries and aqueous supercapacitors. The superior performance of composite electrode is ascribed to high electrical conductivity, fast ionic diffusion rate, and the reduction of work function after the incorporation of Ni2+ ions based on the electrochemical kinetics analysis and density functional theory calculation. In summary, this work puts forward a facile strategy to construct high electrochemical performance electrode for lithium-ion batteries and aqueous supercapacitors. [Display omitted] [ABSTRACT FROM AUTHOR]

Room temperature processed Au/a-IZO (amorphous indium zinc oxide) bilayers are synthesized and systematically studied. Unexpectedly high conductivity of 1.2 × 10 5 Scm −1 and mobility of 65.6 cm 2 V −1 s −1 are achieved for Au/a-IZO bilayer samples prepared under specific conditions. The conduction mechanisms are analyzed. An optimum FOM (figure of merit) value of 40 Ω −1 is obtained, which is ∼3 times higher than that of an ITO film. The optimum Au/a-IZO bilayer sample is successfully applied as counter electrode of DSSC (dye sensitized solar cells). [ABSTRACT FROM AUTHOR]