PSS Structure Research Articles

Textile Organic Electrochemical Transistor for Non-Invasive Glucose Sensing

The global rise in diabetes has highlighted the urgent need for continuous, non-invasive health monitoring solutions. Traditional glucose monitoring methods, which are invasive and often inconvenient, have created a demand for alternative technologies that can offer comfort, accuracy, and real-time data. In this study, the development of a textile-based organic electrochemical transistor (OECT) is presented, designed for non-invasive glucose sensing, aiming to integrate this technology seamlessly into everyday clothing. The document details the design, optimization, and testing of a one-component textile-based OECT, featuring a porous PEDOT:PSS structure and a glucose oxidase-modified electrolyte for effective glucose detection in sweat. The research demonstrates the feasibility of using this textile-based OECT for non-invasive glucose monitoring, with enhanced sensitivity and specificity achieved through the integration of glucose oxidase within the electrolyte and the innovative porous PEDOT:PSS design. These findings suggest a significant advancement in wearable health monitoring technologies, providing a promising pathway for the development of smart textiles capable of non-invasively tracking glucose levels. Future work should focus on refining this technology for clinical use, including individual calibration for accurate blood glucose correlation and its integration into commercially available smart textiles.

Straightforward Production Methods for Diverse Porous PEDOT:PSS Structures and Their Characterization.

Porous conductive polymer structures, in particular Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) structures, are gaining in importance due to their versatile fields of application as sensors, hydrogels, or supercapacitors, to name just a few. Moreover, (porous) conducting polymers have become of interest for wearable and smart textile applications due to their biocompatibility, which enables applications with direct skin contact. Therefore, there is a huge need to investigate distinct, straightforward, and textile-compatible production methods for the fabrication of porous PEDOT:PSS structures. Here, we present novel and uncomplicated approaches to producing diverse porous PEDOT:PSS structures and characterize them thoroughly in terms of porosity, electrical resistance, and their overall appearance. Production methods comprise the incorporation of micro cellulose, the usage of a blowing agent, creating a sponge-like structure, and spraying onto a porous base substrate. This results in the fabrication of various porous structures, ranging from thin and slightly porous to thick and highly porous. Depending on the application, these structures can be modified and integrated into electronic components or wearables to serve as porous electrodes, sensors, or other functional devices.

Transfer-printing of patterned PEDOT:PSS structures for bendable, stretchable and biodegradable electronics

A novel technique to transfer-print variously treated PEDOT:PSS films onto stretchable substrates, including a patterning strategy and electrical and morphological analyses is presented to pave the way for advancements in stretchable electronics.

Fabrication and Characterization of Silicon Nanowires Heterojunction Solar Cell

Silicon nanowire arrays (SiNWs) are created utilizing the metal-assisted chemical etching method with an Ag metal as a catalyst and different etching time of 15, 30, and 60 minutes using n-Si (100). Physical properties such as structural, surface morphology, and optical properties of the prepared SiNWs are studied. The diameter of prepared SiNWs ranged from 20 to 280 nm, and the reflectance in the visible part of the wavelength spectrum was less than 1% for all prepared samples. The obtained energy gap of prepared SiNWs was around 2 eV, which is higher than the energy gap of bulk silicon. X-ray diffraction (XRD) has diffraction peaks at 68.70o for all prepared samples. The heterojunction solar cell was fabricated based on the n-SiNWs/ P3HT/PEDOT: PSS structure. The heterojunction solar cell produced for 60 minutes has the highest Jsc of 11.55 mA.cm-2 and a conversion efficiency of 0.93%. Based on SiNWs prepared for etching time of 15 min, the solar cell demonstrated Jsc and Voc of 2.73 mA/cm2 and 0.46 V, respectively, and a conversion efficiency of 0.34%.

An electrolyte-free electrochromic device using aluminum as counter electrode material

In this study, a novel all-solid-state electrochromic device (ECD) free of indium tin oxide (ITO), tungsten(VI) oxide (WO3), and Li+ or any other liquid/gel electrolytes was prepared by a cost-effective and industrially applicable spray coating technique. The device configuration consists of a pre-formed Al-coated glass substrate for use as a counter electrode in the fabrication of an ECD with a glass/Al/Alq3/PEDOT:PSS structure. The fabricated device (2.5 × 4.0 cm2) demonstrated a reversible color change between a light-blue (off) and dark-blue (on) state, with good and homogeneous contrast. The ECD started coloring at − 0.5 V and was completely colored at – 2.0 V, showing various tones of blue according to the applied voltages. The coloration efficiency was 174.62 cm2/C and the cycle stability was achieved at least 150 times.

Optimization configuration model and application of product service system based on low-carbon design

Most PSS configuration models only consider the value proposition of customers and PSS providers, while little attention has been paid to the value proposition of the environment. In this paper, a novel optimization model of PSS configuration is proposed based on low-carbon design. A new method for calculating the carbon footprint of the product modules and service modules in PSS is proposed. A new greenhouse gas (GHG)-PSS structure tree (G-PS3T) is established based on a bill of materials and a PSS structure tree (PS3T) to express the carbon footprint of a PSS. A novel optimization model for PSS configuration with customer satisfaction, profit, and carbon footprint as the optimization objectives is proposed, and a solver method based on the non-dominated sorted genetic algorithm-II (NSGA-II) is established to obtain the optimal configuration solutions for PSS modules. An automated guided vehicle (AGV)-PSS (AGV-PSS) configuration of enterprise A suggests that the proposed PSS configuration optimization model can significantly reduce the average carbon emissions by 32.33 %. The configuration model and optimization method proposed in this paper are effective to obtain low-carbon PSS schemes that satisfy the value proposition of multi-stakeholders in the early design stage.

3D organic bioelectronics for electrical monitoring of human adult stem cells.

Three-dimensional in vitro stem cell models have enabled a fundamental understanding of cues that direct stem cell fate. While sophisticated 3D tissues can be generated, technology that can accurately monitor these complex models in a high-throughput and non-invasive manner is not well adapted. Here we show the development of 3D bioelectronic devices based on the electroactive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)-(PEDOT:PSS) and their use for non-invasive, electrical monitoring of stem cell growth. We show that the electrical, mechanical and wetting properties as well as the pore size/architecture of 3D PEDOT:PSS scaffolds can be fine-tuned simply by changing the processing crosslinker additive. We present a comprehensive characterization of both 2D PEDOT:PSS thin films of controlled thicknesses, and 3D porous PEDOT:PSS structures made by the freeze-drying technique. By slicing the bulky scaffolds we generate homogeneous, porous 250 μm thick PEDOT:PSS slices, constituting biocompatible 3D constructs able to support stem cell cultures. These multifunctional slices are attached on indium-tin oxide substrates (ITO) with the help of an electrically active adhesion layer, enabling 3D bioelectronic devices with a characteristic and reproducible, frequency dependent impedance response. This response changes drastically when human adipose derived stem cells (hADSCs) grow within the porous PEDOT:PSS network as revealed by fluorescence microscopy. The increase of cell population within the PEDOT:PSS porous network impedes the charge flow at the interface between PEDOT:PSS and ITO, enabling the interface resistance (R1) to be used as a figure of merit to monitor the proliferation of stem cells. The non-invasive monitoring of stem cell growth allows for the subsequent differentiation 3D stem cell cultures into neuron like cells, as verified by immunofluorescence and RT-qPCR measurements. The strategy of controlling important properties of 3D PEDOT:PSS structures simply by altering processing parameters can be applied for development of a number of stem cell in vitro models as well as stem cell differentiation pathways. We believe the results presented here will advance 3D bioelectronic technology for both fundamental understanding of in vitro stem cell cultures as well as the development of personalized therapies.

Fully printed ZnO-based valency-change memories for flexible and transparent applications

Printable and flexible memory devices have attracted a great deal of attention in several emerging technological applications for the development of flexible electronics, such as interconnections/wearables/smart devices for the internet of things (IoT). In this work, we report on the fabrication of flexible, transparent, and fully inkjet-printed resistive random access memory (ReRAM) cells using poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/ZnO/PEDOT:PSS structures. The electrical characteristics were studied, including the determination of space charge limited conduction (SCLC) as the dominant charge transport mechanism. In addition, the bending performance and the transparency of the devices was tested in order to confirm the reliable operation and reproducibility of the cells. The switching for the printed structures of PEDOT:PSS/ZnO/PEDOT:PSS was led through the formation and dissolution of a stable oxygen vacancy filament, as confirmed by conductive atomic force microscopy. While the conduction mechanism for the high resistance state (HRS) was attributed to the SCLC mechanism. The switching of the memory cells, their endurance and retention properties were analysed and indicated the stability of the HRS and low resistance state for more than 104 cycles and 105 s comparable to ZnO-based ReRAM produced by clean-room techniques. The study of the mechanical flexibility of the cells shows that up to 700 bending cycles can be reached without significantly changing the switching characteristics.

Self-powered, ultraviolet-to-near infrared broadband photodetector based on Ag-doped CsPbI3/PEDOT:PSS heterojunction.

Metal halide perovskites are studied for photodetection applications because of their outstanding optical and electrical properties. A self-powered ultraviolet-to-near infrared broadband photodetector based on a Ag-doped CsPbI3/PEDOT:PSS heterojunction was investigated. The photodetector using a CsPbI3:Ag/PEDOT:PSS heterostructure with a planar photoconductive structure operated over a broad 355-1560 nm wavelength range in self-powered mode. A terahertz signal was modulated with the CsPbI3:Ag/PEDOT:PSS structure at low optical excitation intensity to investigate its photodetection mechanism. The experimentally designed detector can present images of the letters "C", "N" and "U" in the visible and near-infrared wavelengths, indicating a potential broadband imaging application.

Weak Molecular Interactions in Organic Composite Dry Film Lead to Degradable, Robust Wireless Electrophysiological Signal Sensing

AbstractLong‐term and highly sensitive electrophysiological signal detection is the primary issue for wearable health monitoring. The critical issues of pre‐gelled wet electrodes as conventional approaches are limited conductivity and low adhesivity owing to the dependence of moisture concentration. Along this line, this paper presents a biocompatible, mechanically robust, water degradable, and intrinsically conductive organic composite dry film electrode based on poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), hydroxyethyl cellulose, and dopamine. The effects on PEDOT:PSS structure transition are studied systematically according to the combination of each component with various analytical methods including morphological, chemical, electrical, and mechanical characterization. The proposed film exhibits high conductivity (292 S m–1) and robust mechano‐electrical stability (only 8% of resistance change under 110 of fully flat‐bended cycles) owing to the weak but synergetic interactions between the components. Furthermore, low noise, clear signal, and long‐term stability for a wireless electrocardiogram and electromyogram signal sensing is achieved using the proposed dry electrode.

Enhanced Lateral Photovoltaic Effects in n-Si/SiO2/PEDOT:PSS Structures.

Organic/silicon hybrid structures have been extensively studied for the application of solar cells due to their high photoelectric conversion efficiency and simple fabrication process. However, studies of lateral photovoltaic effects (LPEs) in the devices are still scarce. Herein, the Si/SiO2/PEDOT:PSS devices were prepared by spin-coating, and showing the lateral photovoltage (LPV) sensitivity of 14.0 mV/mm at room temperature, which is higher than the control samples of Si/SiO2 (0.1 mV/mm) and Si/PEDOT:PSS (9.0 mV/mm) structures. With the decrease in temperature, the lateral photovoltage increases initially, and reaches a peak at around 210 K, then drops accordingly. The enhancement of LPE can be mainly ascribed to the formation of the p-n junction and the native oxide layer at the organic/inorganic interface.

Effect of Quencher, Geometry, and Light Outcoupling on the Determination of Exciton Diffusion Length in Nonfullerene Acceptors

The correct determination of the exciton diffusion length (LD) in novel organic photovoltaics (OPV) materials is an important, albeit challenging, task required to understand these systems. Herein, a high‐throughput approach to probe LD in nonfullerene acceptors (NFAs) is reported, that builds upon the conventional photoluminescence (PL) surface quenching method using NFA layers with a graded thickness variation in combination with spectroscopic PL mapping. The method is explored for two archetypal NFAs, namely, ITIC and IT‐4F, using PEDOT:PSS and the donor polymer PM6 as two distinct and practically relevant quencher materials. Interestingly, conventional analysis of quenching efficiency as a function of acceptor layer thickness results in a threefold difference in LD values depending on the specific quencher. This discrepancy can be reconciled by accounting for the differences in light in‐ and outcoupling efficiency for different multilayer architectures. In particular, it is shown that the analysis of glass/acceptor/PM6 structures results in a major overestimation of LD, whereas glass/acceptor/PEDOT:PSS structures give no significant contribution to outcoupling, yielding LD values of 6−12 and 8−18 nm for ITIC and IT‐4F, respectively. Hence, practical guidelines for quencher choice, sample geometries, and analysis approach for the accurate assessment of LD are provided.

Influence of the molecular weight and size distribution of PSS on mixed ionic-electronic transport in PEDOT:PSS.

The commercially available polyelectrolyte complex poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is ubiquitous in organic and hybrid electronics. As such, it has often been used as a benchmark material for fundamental studies and the development of new electronic devices. Yet, most studies on PEDOT:PSS have focused on its electronic conductivity in dry environments, with less consideration given to its ion transport, coupled ionic-electronic transport, and charge storage properties in aqueous environments. These properties are essential for applications in bioelectronics (sensors, actuators), charge storage devices, and electrochromic displays. Importantly, past studies on mixed ionic-electronic transport in PEDOT:PSS neglected to consider how the molecular structure of PSS affects mixed ionic-electronic transport. Herein, we therefore investigated the effect of the molecular weight and size distribution of PSS on the electronic properties and morphology of PEDOT:PSS both in dry and aqueous environments, and overall performance in organic electrochemical transistors (OECTs). Using reversible addition-fragmentation chain transfer (RAFT) polymerization with two different chain transfer agents, six PSS samples with monomodal, narrow (Đ = 1.1) and broad (Đ = 1.7) size distributions and varying molecular weights were synthesized and used as matrices for PEDOT. We found that using higher molecular weight of PSS (M n = 145 kg mol-1) and broad dispersity led to OECTs with the highest transconductance (up to 16 mS) and [μC * ] values (~140 F·cm-1V-1s-1) in PEDOT:PSS, despite having a lower volumetric capacitance (C * = 35 ± 4 F cm-3). The differences were best explained by studying the microstructure of the films by atomic force microscopy (AFM). We found that heterogeneities in the PEDOT:PSS films (interconnected and large PEDOT- and PSS-rich domains) obtained from high molecular weight and high dispersity PSS led to higher charge mobility (μ OECT ~ 4 cm2V-1s-1) and hence transconductance. These studies highlight the importance of considering molecular weight and size distribution in organic mixed ionic-electronic conductor, and could pave the way to designing high performance organic electronics for biological interfaces.

Simulation and fabrication of an ammonia gas sensor based on PEDOT:PSS

PurposeThe purpose of this study is use to density functional theory (DFT) to investigate the molecular adsorption by PEDOT:PSS for different doping levels. DFT calculations are performed using the SIESTA code. In addition, the non-equilibrium Green’s function method is used within the TranSIESTA code to determine the quantum transport properties of molecular nanodevices.Design/methodology/approachDensity functional theory (DFT) is used to investigate the molecular adsorption by PEDOT:PSS for different doping levels. DFT calculations are performed using the SIESTA code. In addition, the non-equilibrium Green’s function method is used within the TranSIESTA code to determine the quantum transport properties of molecular nanodevices.FindingsSimulation results show very good sensitivity of Pd-doped PEDOT:PSS to ammonia, carbon dioxide and methane, so this structure cannot be used for simultaneous exposure to these gases. Silver-doped PEDOT:PSS structure provides a favorable sensitivity to ammonia in addition to exhibiting a better selectivity. If the experiment is repeated, the sensitivity is increased for a larger concentration of the applied gas. However, the sensitivity will decrease at a higher ratio than smaller concentrations of gas.Originality/valueThe advantages of the proposed sensor are its low-cost implementation and simple fabrication process compared to other sensors. Moreover, the proposed sensor exhibits appropriate sensitivity and repeatability at room temperature.

LIFE PHASES MODULARISATION OF PRODUCT-SERVICE SYSTEMS

AbstractProduct Service Systems (PSS) are increasingly important for companies. They enable a multitude of advantages, including the ability to offer customers even more individual customised solutions. However, PSS can also cause negative effects for companies. For example, PSS increase the complexity within companies. In order to cope with this complexity, the modularisation of PSS is frequently suggested in literature. However, existing approaches for modularisation only consider functional reasons for module composition and neglect the product-strategic aspects. This paper introduces a new approach for the modularisation of PSS, which combines functional and product-strategic aspects into one approach. To achieve this, a separate modular structure is developed for each life phase. Following this, these are harmonised across all life phases. This enables the advantages of the modular PSS structure to be used in all life phases. A PSS family of laser processing machines is used to illustrate the new developed approach.

Tuning of PEDOT:PSS synthesis via multiple doping for enhanced electrical conductivity

AbstractThe poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) synthesis conditions were refined to obtain extremely high electrical conductivity. PEDOT:PSS was synthesized by chemical oxidative polymerization under the effects of acid types and concentrations, EDOT:PSS weight ratio, and surfactant types and concentrations. The PEDOT:PSS synthesized with EDOT:PSS weight ratio of 0.5:5.5 in 0.1 mol L−1 HClO4 provided the highest electrical conductivity of 1.04 × 104 ± 188 S cm−1, not previously reported. The enhanced electrical conductivity can be attributed to the combinatorial primary doping by selective ions (ClO4−, PSS−, SO42−) generating a suitable PEDOT:PSS structure with high carrier number and electron mobility, as consistently verified using Fourier transform infrared spectroscopy, UV–visible spectrometry, X‐ray photoelectron spectrometry and thermogravimetric analysis. The refined synthesis opens a new route for PEDOT:PSS nanoparticles to be used in various electronic applications which require the starting nontoxic organic material to be highly conductive. © 2021 Society of Industrial Chemistry.

A TOGAF-based Framework for the Development of Sustainable Product-Service Systems

Companies around the world have sought to produce sustainable products and services with less impact. The impact produced by the COVID-19 pandemic showed that the supply Systems Product-Service (PSS) with an emphasis on sustainability has grown to become one of the main strategic approaches used. The existence of an automated framework that can assist designers in creating a PSS that encompasses the preparation of products and services simultaneously, from its initial stages, has become extremely important. Thus, the objective of this article is to develop a Framework capable of organizing the necessary information for the development of product and service in an integrated way, using the development of information architectures rationale, such as TOGAF, so that in all stages there is fluidity and there are no duplicity terms in its development. The use of information architecture development methods to develop the PSS structure presents a great opportunity to carry out its mapping, thus ensuring that the model is suitable to represent real-world situations.

Highly Conductive PEDOT:PSS Thin Films with Two-Dimensional Lamellar Stacked Multi-Layers.

Conjugated polymers are desired as organic electrode materials because of their functional properties such as solution process, low cost, and transparency. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), in particular, shows the highest applicability, but its heterogeneous structure presents limitations in terms of electrical conductivity. In this study, a facile method to fabricate multi-layered thin films with higher ordered structures was developed. Through the etching process with H2SO4 and dimethyl sulfoxide(DMSO), the insulated rich-PSS was removed from the upper layer to improve its electrical properties and rearrange the PEDOT molecular structures. The thickness of PEDOT:PSS thin films was experimentally optimized to maximize the enhancement of carrier mobility via a layer-by-layer (LBL) process. The combined method, consisted of etching and the LBL process, showed the improvement of the charge carrier mobility from 0.62 to 2.80 cm2 V−1 s−1. The morphology and crystallinity of the ordered PEDOT:PSS structure were investigated by X-ray photoemission spectroscopy (XPS), Raman, and X-ray diffraction (XRD). As a result, two-dimensional lamellar-stacked PEDOT:PSS thin films were fabricated through the repetitive etching and LBL process. The optimized PEDOT:PSS thin film showed an excellent electrical conductivity of 3026 S cm−1, which is 3.8 times higher than that of the pristine film (801 S cm−1).

P‐85: Development of High‐yield Laser Lift‐off Process for Micro LED Display

This paper reports our developments for Micro LED laser lift‐off which is a very important step in Micro LED mass transfer process. By selecting the temporary bonding material, optimizing laser power intensity, and using PSS structure, the yield of Micro LED laser lift‐off can reach 99% for more than 5000 LEDs. This technical developments is of great potential for promoting high‐yield mass transfer technology to realize commercial Micro‐LED displays.

Significant enhancement of out-coupling efficiency for yarn-based organic light-emitting devices with an organic scattering layer

Yarn-based organic light-emitting devices (YOLEDs) have emerged as candidates for potential applications in electronic textiles and wearable electronics. However, the efficiency of YOLEDs is lower than that of conventional OLEDs based on glass substrates because of the loss of light in the interface between the yarn and the organic layers. This paper reports an enhanced out-coupling efficiency when Norland Optical Adhesive 63 (NOA63): Bathophenanthroline (Bphen) particles are used as an organic scattering layer (OSL) for applications in high-efficiency YOLEDs. The RMS roughness of the yarn/OSL/PEDOT:PSS structures (4.3 nm) is drastically reduced in comparison with that of yarn (19.7 nm). Furthermore, the transmittance intensities at 515 nm of yarn with and without an OSL containing Bphen particles are 87% and 82%, respectively, and the luminance of YOLEDs with Bphen particles in the OSL (194.1 cd/cm2) is 41.7 cd/cm2 larger than that without Bphen particles (152.4 cd/cm2) due to the scattering of light from those particles. Moreover, at 515 nm, the electroluminescence (EL) intensity of YOLEDs with Bphen particles in the OSL is 1.3 times larger than that of the YOLEDs without the particles. This successful demonstration of enhanced luminescence and enhanced EL for YOLEDs based on an OSL containing Bphen particles indicates a potential for applications of YOLEDs in next-generation wearable display systems.