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A novel CuS grafted PEDOT:PSS conducting paper-based electrochemical immunosensor has been successfully fabricated for the detection of EpCAM antigen. Electrical conductivity is further improved by doping the CuS@PEDOT:PSS/WP electrode with different organic solvents such as N,N-dimethyl formamide (DMF), N,N-dimethyl acetamide (DMA), ethylene glycol (EG) and dimetyl sulfoxide (DMSO). It is observed that DMSO doped conducting paper shows the highest conductivity (6.1 × 10−2 S/cm) among all these solvents. This low cost, biodegradable electrochemical paper-based immunosensor (BSA/anti-EpCAM/EP) possesses a broad linear range from 0.01 pg/mL to 1000 ng/mL for EpCAM antigen detection. The immunosensor is found to have high sensitivity of 104.31 μA pg−1 mL. This conducting paper based immunosensor is further used to detect EpCAM antigen in human serum samples, thereby confirming a cost effective clinical tool over other costly conventional techniques. • An electrochemical paper-based immunosensor has been designed using CuS and PEDOT:PSS. • This low cost and flexible platform may be a promising candidate over other costly conventional electrodes. • It exhibits high sensitivity of 104.31 μA pg−1 mL in broad range of 0.01 pg/mL to 1000 ng/mL, for EpCAM detection. • The clinical applicability and validity has been checked with human serum sample. [ABSTRACT FROM AUTHOR]

Analysis of neurotransmitters such as dopamine (DA) is essential to better understand brain-related mechanisms. In this context, paper-based electroanalytical devices are promising alternatives to the current techniques for affordable, user-friendly molecular quantitation. Conductive carbon-based and polymer-based inks such as carbon nanotubes (CNT) and polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) have shown several advantageous properties, such as resistance to the DA fouling occurring during the electrochemical detection. Here, the electrical and electrochemical properties of paper devices prepared from mixtures of the inks were investigated, as well as their DA detection performance (limit of detection and fouling resistance). The properties of these paper electrodes were found to be directly impacted by the choice of ink. CNT-based electrodes are more resistive than the PEDOT:PSS based ones, which are more capacitive. Also, electrodes with undercoats of CNT and overcoats of PEDOT:PSS, doped with organic solvents, better resist DA fouling and have lower limits of detection. The combination of carbon-based and polymer-baser inks allowed for optimizing DA detection, and highlights the versatility and adaptability of paper-based electrode fabrication. [ABSTRACT FROM AUTHOR]

This study describes an easy and cheap inkjet printing method for producing a paper-based gas sensor consisting of a composite film made of graphene oxide and poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) (PEDOT:PSS). A glossy paper substrate is an inkjet printed with ink made by dispersing graphene oxide in a PEDOT:PSS conducting polymer solution to test its ability to detect ammonia (NH3) at ambient temperature. The presence of few-layer graphene oxide in the PEDOT:PSS copolymer and the existence of π-π interactions between graphene oxide and PEDOT:PSS are confirmed by Fourier transform infrared spectroscopy, UV–Visible spectrophotometer, and X-ray diffraction. In a small concentration range of 1–100 ppm at ambient temperature, the ink-jet printed graphene oxide-PEDOT:PSS gas sensor displays strong responsiveness and good selectivity to NH3. The study found that NH4 is a strong donor in the ammonia gas produced by a bubble system of ammonia water, with NH4 molecules being ideal candidates for molecular doping of graphene. The H2O molecule can facilitate quick desorption by converting NH3 to NH4. The interaction between graphene oxide and NH3 molecules is weak. The attained gas-sensing performance may be attributed to the increased specific surface area of graphene oxide and enhanced interactions between the sensing film and NH3 molecules via π and lone pair electron network. The NH3-sensing mechanisms of the flexible printed gas sensor are based on the competitive interaction of ammonia on the sensor, adsorption and dissociate ionization on the sensor surface. [ABSTRACT FROM AUTHOR]

Harvesting renewable mechanical energy is envisioned as a promising and sustainable way for power generation. Many recent mechanical energy harvesters are able to produce instantaneous (pulsed) electricity with a high peak voltage of over 100 V. However, directly storing such irregular high‐voltage pulse electricity remains a great challenge. The use of extra power management components can boost storage efficiency but increase system complexity. Here utilizing the conducting polymer PEDOT:PSS, high‐rate metal‐free micro‐supercapacitor (MSC) arrays are successfully fabricated for direct high‐efficiency storage of high‐voltage pulse electricity. Within an area of 2.4 × 3.4 cm2 on various paper substrates, large‐scale MSC arrays (comprising up to 100 cells) can be printed to deliver a working voltage window of 160 V at an ultrahigh scan rate up to 30 V s−1. The ultrahigh rate capability enables the MSC arrays to quickly capture and efficiently store the high‐voltage (≈150 V) pulse electricity produced by a droplet‐based electricity generator at a high efficiency of 62%, significantly higher than that (<2%) of the batteries or capacitors demonstrated in the literature. Moreover, the compact and metal‐free features make these MSC arrays excellent candidates for sustainable high‐performance energy storage in self‐charging power systems. [ABSTRACT FROM AUTHOR]

The development and optimization of a paper-based ion-selective organic electrochemical transistor (IS-OECT) with an outstanding analytical performance is presented. The combination of thick-film transistor technology with a suitable optimization of the ion-selective membrane composition and thickness allows reaching sensitivities of up to 2.50 mA/decade, which is more than one order of magnitude higher than other similar devices reported up to date. The system shows good selectivity, allowing the detection of low concentrations of potassium in high saline concentrations, and a linear range from 0.1 mM to 100 mM, which covers the relevant clinical range of K+ in blood. A calibration curve for K+ in artificial serum between 1 and 10 mM shows changes in concentrations down to 0.05 mM can be discriminated. Furthermore, the device can be made with a simple manufacturing process, such as drop casting, on low-cost substrate materials and can be operated with a gate voltage of 0 V. This IS-OCET offers promising avenues for developing ion-sensing platforms for the point of need. [Display omitted] • Novel paper-based manufacturing approach to build ion-selective OECT. • Thick-film technology combined with thin ion-selective membrane. • Potassium OECT with outstanding sensitivity. • Enhanced detection of K+ in artificial serum. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two-step surface post-processing with Femtosecond laser irradiation and ionic liquids were employed. • Illustrate an effect of Femtosecond laser irradiation and ionic liquids. • PEDOT:PSS films exhibit a high power factor of 40.89 μW·m−1·K−2. • A flexible thermoelectric device using human body temperature to generate electricity is designed. Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has garnered significant considerable interest in the field of flexible thermoelectric films owing to its very low thermal conductivity, highly adjustable electrical conductivity (σ) and Seebeck coefficient (S). However, improving the σ and S of PEDOT:PSS simultaneously remains challenging for achieving efficient thermoelectrics. In this paper, we proposed a two-step process involving femtosecond laser irradiation and ionic liquid (IL) 1-Ethyl-3-MethylImidazolium DiCyAmide treatment to enhance the thermoelectric properties of PEDOT: PSS thin films. This finding revealed that the increase in PEDOT: PSS conductivity was attributed to both laser irradiation and the post-treatment with IL, in which the former enabled the efficient elimination of insulating PSS from the surface of the conductive polymer, the latter further contributed to the decoupling of PEDOT and PSS. The enhanced Seebeck coefficient was due to the ion exchange resulting from IL post-processing, which regulated the PEDOT doping level. By employing laser irradiation and surface treatment with IL, the modified PEDOT:PSS films showed a S of 20.63 μV·K−1, a σ of 960.7 S·cm−1, and a power factor (PF) of 40.89 μW·m−1·K−2. Furthermore, a thermoelectric device was developed which can generate a voltage of 0.8 mV at a temperature difference of 11.7 K. [ABSTRACT FROM AUTHOR]

• Acrylamide can neutralize the acidity of the hole-transport layer. • Acrylamide can optimize the quality of the FASnI 3 perovskite film. • The efficiency of FASnI 3 perovskite solar cells is increased by almost 46 %. The quality of the hole transport layer (HTL) is crucial for the overall efficiency of the perovskite solar cells. Although poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT:PSS) has been widely used as HTL for the perovskite solar cells, there is still room for further improvement of PEDOT:PSS by optimizing its energy level matching and the hole transfer efficiency. Based on the present issues of applying PEDOT:PSS as HTL in tin-based perovskite solar cells, the Lewis alkali acrylamide (AM), which contains both carbon-carbon double bond and the electrophilic amide group, is applied as the dopant in PEDOT:PSS solution. By analyzing the surface morphology and the crystal structure, it is revealed that AM can effectively improve both the quality and crystallinity of the formamidinium tin tri-iodide (FASnI 3) perovskite film, with the defects of the perovskite film greatly suppressed. The grain size of the modified FASnI 3 perovskite is observed to increase with the surface roughness reducing at the same time, along with the charge recombination resistance of the FASnI 3 perovskite film increasing. As a result, the modified devices have a higher short-circuit current, fill factor as well as power conversion efficiency. The characterization of the surface contact angle indicates that a more hydrophobic surface is formed as for the FASnI 3 perovskite film, which could efficiently retard the ambient vapor penetrating into the perovskite film. [ABSTRACT FROM AUTHOR]