Capacitive performance of electrodeposited PEDOS and a comparative study with PEDOT

Ultraviolet Photodetector Based on Poly(3,4-Ethylenedioxyselenophene)/ZnO Core-Shell Nanorods p-n Heterojunction

In this work, we successfully assembled an organic-inorganic core-shell hybrid p-n heterojunction ultraviolet photodetector by the electropolymerization deposition of poly(3,4-ethylenedioxyselenophene) (PEDOS) on the surface of zinc oxide nanoarrays (ZnO NRs). The structures of composite were confirmed by FTIR, UV-Vis, XRD and XPS. Mott-Schottky analysis was used to study the p-n heterojunction structure. The photodetection properties of ZnO NRs/PEDOS heterojunction ultraviolet photodetector were systematically investigated current-voltage (I-V) and current-time (I-t) analysis under different bias voltages. The results showed that PEDOS films uniformly grew on ZnO NRs surface and core-shell structure was formed. The p-n heterojunction structure was formed with strong built-in electric field between ZnO NRs and PEDOS. Under the irradiation of UV light, the device showed a good rectification behavior. The responsivity, detection rate and the external quantum efficiency of the ultraviolet photodetector reached to 247.7 A/W, 3.41 × 10¹² Jones and 84,000% at 2 V bias, respectively. The rise time (τ_r) and fall time (τ_f) of ZnO NRs/PEDOS UV photodetector were obviously shortened compared to ZnO UV photodetector. The results show that the introduction of PEDOS effectively improves the performance of the UV photodetector.

Electropolymerization of EDOT in an anionic surfactant-stabilized hydrophobic ionic liquid-based microemulsion

Here, an anionic surfactant [AOT]^- (bis-(2-ethylhexyl) sulfosuccinate)-stabilized H₂O/[Omim][PF₆] (1-octyl-3-methylimidazolium hexafluorophosphate) microemulsion has been tested for the first time as a medium for the electropolymerization of 3,4-ethylenedioxythiophene (EDOT). To formulate AOT-stabilized [Omim][PF₆]-based microemulsions of different water contents, the phase triangle was determined at 35 °C. Measurements of the conductivities of the microemulsions, their solubilization capacities toward EDOT and their catalytic effects on EDOT electrooxidation show that the present [AOT]^--stabilized ionic liquid microemulsion is a good medium for EDOT electropolymerization. Studies on the process of the electropolymerization of EDOT in this [Omim][PF₆]-based microemulsion indicate that the water content (i.e., microstructure) of the microemulsion medium is an important factor affecting the onset potential and the deposition rate of the PEDOT. The morphology and the doping level of the as-prepared PEDOT are also found to be correlated with the water content of the ionic liquid microemulsion. The microemulsion with higher water content results in a PEDOT with better electroactivity and higher doping levels. FTIR spectra and XPS analysis show that the PEDOT electrosynthesized in the microemulsion is co-doped by both [AOT]^- and [PF₆]^-. Compared with the neat [Omim][PF₆], the use of the ionic liquid microemulsions can reduce not only the consumption of the expensive ionic liquid, but also the onset potential for the electrooxidation of EDOT. Moreover, by tuning the water content of the medium, the electropolymerization of PEDOT and its electrochemical properties could be regulated accordingly. Under the identical deposited charge, the PEDOT originated from the high water content microemulsion (50% H₂O μE) has a higher specific capacitance (124 F g^-1) than that from neat [Omim][PF₆] (117 F g^-1). It follows that the present ionic liquid microemulsion is a good medium for EDOT electropolymerization. The present study opens up a new route for the green and low-cost electrochemical preparation of high-performance PEDOT.

Electrochemical sensor formed from poly(3,4-ethylenedioxyselenophene) and nitrogen-doped graphene composite for dopamine detection

In this study, an electrochemical sensor for dopamine (DA) detection has been developed by a composite of poly(3,4-ethylenedioxyselenophene) (PEDOS) and nitrogen-doped graphene (PEDOS/N-Gr) using an in situ polymerization method. Its structure and properties were then compared with those of the composites of poly(3,4-ethylenedioxythiophene) (PEDOT)/nitrogen-doped graphene (PEDOT/N-Gr), which were prepared by the same methods. FT-IR, Raman, UV-vis, XPS, mapping and SEM investigated the structure and morphology of these composites. These revealed that PEDOS/N-Gr had a higher conjugation degree than PEDOT/N-Gr. The synergetic effect between PEDOS and N-Gr was beneficial for the formation of a homogenous surface coating. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods were conducted for electrochemical detection of DA. Compared with PEDOT/N-Gr, the PEDOS/N-Gr displayed an enhanced sensitivity and electrocatalytic performance for DA detection with linear ranges of 0.008-80 μM (PEDOT/N-Gr: 0.04-70 μM) and limits of detection (LOD) of 0.0066 μM (S/N = 3) (PEDOT/N-Gr: 0.018 μM (S/N = 3)).

Recent advances in poly(3,4-ethylenedioxyselenophene) and related polymers

This review highlights the recent progress in synthesis, properties, applications and future outlook of PEDOS based conjugated polymers.

Relationship between Charge Transfer Diffusion Coefficients and Doping Level for electro generated thin PEDOT films on ITO

Thin films of poly-3,4-ethylene dioxythiophene (PEDOT) were electrodeposited on transparent electrodes of indium tin oxide (ITO) using potentiostatic regime. These films had thicknesses ranging from 15 nm to 60 nm and were studied using UV-vis absorption and chronoamperometric techniques in monomer-free tetrabutylammonium perchlorate/acetonitrile solutions. The charge transfer diffusion coefficient (D) of the films were calculated using Cottrell model for a wide range of potential steps from −1.60 to 1.60 V vs. Ag°/AgNO3. For p-doped films, the highest diffusion coefficients were obtained when a potential of 0.70 V was applied. Moreover, a direct relationship between film thickness and their diffusion coefficients was found for thin PEDOT films showing D values up to 1.4 × 10−9 cm2 s−1 for 60 nm thickness films. These values are remarkably higher than the D of 1.8 × 10−11 cm2 s−1 obtained for spin-coated PEDOT: PSS films of similar thickness.