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The fabrication of a fully printed, lead-free, polymer piezoelectric transducer is presented and the characterization of its structural, dielectric, and ferroelectric properties at different processing stages is demonstrated. The performance of poly(vinylidene fluoride-trifluoroethylene) transducers with resonance frequency analyses, acoustic power measurements, and pulse-echo experiments is evaluated. Notably, for the first time for a fully printed transducer, an optimal performance in the medical ultrasound range (1 W cm(-2), which is promising for applications in epidermal and wearable electronics. Overall, the findings provide a strong foundation for future research in the area of flexible ultrasound transducers., Advanced Materials Technologies, ISSN:2365-709X

Novel inorganic-organic hybrid photochromic and fluorescent ink for anticounterfeiting documents was developed using a pigment/resin ink formula enclosing a long-lived luminescent inorganic pigment with good thermal photostability. The produced ink exhibited an optimal excitation wavelength at 360 nm with an absorption colour and fluorescence changes in the printed document. To develop a transparent printed film from pigment/resin ink, the phosphorescent pigment has to be well dispersed physically without agglomeration. The pigment/resin hybrid was applied effectively onto commercial cellulose paper sheets using screen-printing technology. An homogeneous photochromic layer was deposited on cellulose paper document surface to afford a considerable greenish-yellow colour as demonstrated by CIE coloration measurements under a UV lamp, even at a pigment concentration as low as 0.1 wt% of the ink formulation. The printed paper sheets exhibited three excitation bands at 235, 274 and 378 nm and three emission bands at 416, 418 and 436 nm. Fluorescence optical microscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and wavelength-dispersive X-ray fluorescence spectrometry of the printed paper sheet were explored. The screen-printed paper sheets displayed a reversible and fast photochromism during ultraviolet irradiation without fatigue. The rheological properties, stability, and printability of the ink were studied.

The development of polymer-based conductive inks has gained increasing interest in the areas of printed and molded electronics. Graphene-based materials are explored in this scope, reduced graphene oxide (rGO) being among the most used conductive filler components of the inks. Herein, rGO is doped with nitrogen to obtain N-rGO; the replacement of oxygen atoms by nitrogen ones increases the electrical conductivity of graphene. Polymer-based conductive inks reinforced with graphene are developed based on polyvinylpyrrolidone (PVP) as polymer binder and dihydrolevoglucosenone (Cyrene) as solvent, leading thus to environmentally friendly conductive inks. Screen-printable inks are optimized in terms of viscosity and adhesion properties, leading to printed films with sheet resistance close to Rs=1ksq1, the graphene:PVP inks being also biocompatible and nontoxic., This work was supported by the Portuguese Foundation for Science and Technology (FCT): projects UID/FIS/04650/2021, UIDB/05256/2020, UIDP/05256/2020, PTDC/FIS-MAC/28157/2017, and PTDC/BTM-MAT/28237/2017, grants SFRH/BPD/110914/2015 (P.C.) and SFRH/BD/145741/2019 (M.F.), and Stimulus of Scientific Employments 2020.04028.CEECIND (C.M.C.) and 2020.04163.CEECIND (C.R.). The authors thank Basque Government Industry Department under the ELKARTEK program and European Union’s Horizon 2020 Programme, ICT-02-2018, Flexible and Wearable Electronics, grant agreement no. 825339, WEARPLEX, wearable multiplexed biomedical electrodes.

Conductive graphene-based inks can be tailored for functional applications and, in particular, for printed electronics. Transparent, flexible, and easy printable materials are nowadays increasingly required for sensing applications. In this context, a capacitive multitouch sensing surface is developed using conductive graphene nanoparticles-based ink with carboxymethyl cellulose as a binder. The rheological properties of the ink are tailored to be printed by the screen-printing technique. The touchscreen is based on printed conductive lines and columns and thus the characteristics of the printed lines are optimized based on the line width and number of printing steps. The optimal printed conditions are 0.5 mm of width and five printing steps, leading to electrical resistance of 2.4 kΩ. The screen-printed flexible touchscreen is composed of 40 columns × 28 rows. An electric circuit and a graphic interface are also developed leading to an 8” touchscreen with multitouch capabilities and fast signal processing., Fundação para a Ciência e Tecnologia (FCT) within the Strategic Project UID/FIS/04650/2021 and grants SFRH/BPD/110914/2015 (P.C.) and SFRH/BD/145741/2019 (M.F.). The authors also thank the Fundo Europeu de Desenvolvimento Regional (FEDER) and Agência Nacional de Inovação (ANI) project with reference POCI-01-0247-FEDER-033566. Basque Government Industry Department under the ELKARTEK programs. Graphenest would like to thank Vitor Abrantes and João França for their contribution in graphene optimization

The high usage of silver in industrial solar cells may limit the growth of the solar industry. One solution is to replace Ag with copper. A screen printable Cu paste is used herein to metallize industrial interdigitated back contact (IBC) solar cells. A novel metallization structure is proposed for making solar cells. Cu paste is applied to replace the majority of the Ag used in IBC cells as busbars and fingers. Cu paste is evaluated for use as fingers, and solar cells are made to test conversion efficiency and reliability. The Cu paste achieves comparably low resistivity, and Cu paste printed cells demonstrate similar efficiency to Ag paste printed cells, with an average efficiency of 23%, and only 4.5 mg W−1 of Ag usage. Also, the solar cells are stable and no Cu in-diffusion is observed under damp heat (85 °C, 85% relative humidity) and thermal stress (200 °C) for 1000 h, respectively. All processes used in this study can be carried out with industrial equipment. These findings reveal a new application for Cu pastes and point to a new direction for reducing Ag utilization and cost.

Book chapter which provides an overview of developments in printing technology from the 15th century to the present day.

Post-treatment was performed for poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films screen-printed on fluorine-doped tin oxide (FTO) substrates, to improve their charge transfer efficiency. Different H2 SO4 solutions, including concentrated H2 SO4 and H2 SO4 diluted with H2 O or dimethyl sulfoxide (DMSO), were adopted during the post-treatment. The adhesion of the as-treated films was evaluated by adhesive tape peeling tests, the surface morphology and vertical charge transfer from the films to the substrates were investigated by current-sensing atomic force microscopy, and the catalytic activities toward I3 - reduction of PEDOT:PSS films were characterized by electrochemical measurements. It is discovered that selecting proper H2 SO4 solutions is crucial to improve the charge transfer efficiency and catalytic performance while maintaining reliable adhesion of the film on the substrates, with H2 SO4 /DMSO performing best as the solution for post-treatment. A mechanistic explanationis proposed based on different interactions among solution, PEDOT:PSS, and the substrate for various post-treatment solutions.

The organic photovoltaic cell (OPV) is composed of multiple layers, and some printing and coating techniques are more suitable than others for a certain type of layer. This paper aims to characterize and compare the most relevant coating and printing techniques that can be used in the manufacture of OPVs. Extensive bibliographic research was carried out on articles published from 1998 to 2020 to identify various aspects OPV, such as the principle of operation, advantages, disadvantages, and which layers can be printed by each technique. The results show that the most used method for the processing of OPVs is spin‐coating. In the studies found, rotation was used to coat the active layer, the electron transport layer, and the hole transport layer. The techniques of pad printing, casting, and meniscus are considered useful in the processing of the active layer. Regarding the deposition of the active layer, hole transport layer, electron transport layer, and anode, the rotogravure, crack matrix, spraying, and brushing techniques were satisfactory. Flexography has been used to form the active layer, electron transport layer, and anode. Screen printing, inkjet printing, and knife/blade coating were used in the processing of the active layer, hole transport layer, electron transport layer, anode, and cathode. All the double slot die coating, curtain coating, and slide coating allows simultaneous processing of multiple layers. Techniques compatible with roll‐to‐roll processing are more likely to be at the center of OPVs in the future, thus making solar photovoltaic technology more competitive

This research study focuses on the application of conductive ink by the screen printing technique to evaluate the potential of creating printed electrodes and to investigate the effect of washing upon electrical resistance and flexibility. Two conductive inks were applied by a conventional screen printing method on four different textile substrates, 100% cotton, 50%/50% cotton/polyester, 100% polyester and 100% polyamide. the inks were also applied on a multifibre fabric. Atmospheric plasma treatment was applied to improve the adhesion to the samples, and the resistance values were compared with those of non-treated samples. the values were measured before and after cleaning and washing tests, which were performed to simulate domestic treatment for garments to predict the behaviour of the inks after normal usage of the fabrics. Comfort properties like stiffness of the fabrics were also evaluated after five and 10 washing cycles. It was observed that PE 825 ink forms a thicker film on the fabric surface, contributing to the loss of flexibility of the textile. However, PE 825 ink also produced the best results in terms of durability and lower values of resistance. Polyamide fabrics lost their conductive property after five washing cycles due to weak bonding between the ink and the fibres, whereas cotton fibres provided the best results., Fundacao para a Ciencia e a TecnologiaPortuguese Foundation for Science and Technology [2C2T-BPD-08-2017, UID/CTM/00264/2019]; Deus ex Machina [NORTE-01-0145-FEDER-000026], Fundacao para a Ciencia e a Tecnologia, Grant/Award Number: 2C2T-BPD-08-2017 and UID/CTM/00264/2019; Deus ex Machina, Grant/Award Number: NORTE-01-0145-FEDER-000026

This paper describes a simple, convenient approach to the fabrication of microband electrodes and microband biosensors based on screen printing technology. These devices were printed in a three-electrode configuration on one strip; a silver/silver chloride electrode and carbon counter electrode served as reference and counter electrodes respectively. The working electrodes were fabricated by screen-printing a water-based carbon ink containing cobalt phthalocyanine for hydrogen peroxide detection. These were converted into a glucose microband biosensor by the addition of glucose oxidase into the carbon ink. In this paper, we discuss the fabrication and application of glucose microband electrodes for the determination of glucose in cell media. The dimensions (100 – 400 microns) of the microband electrodes result in radial diffusion, which results in steady state responses in the absence of stirring. The microband biosensors were investigated in cell media containing different concentrations of glucose using chronoamperometry. The device shows linearity for glucose determination in the range 0.5 mM to 2.5 mM in cell media. The screen-printed microband biosensor design holds promise as a generic platform for future applications in cell toxicity studies.

This study presents preliminary results for tubular anode-supported solid oxide fuel cells (SOFCs) fabricated by a novel method based on tape casting. A multilayer tape cast was prepared by successive casting of the anode support, anode functional layer, and electrolyte. The tape cast was rolled into a tube, and the ends of the tape were joined by solvent-assisted lamination. The sample was co-fired at 1400°C, followed by screen printing and sintering of the cathode at 1150°C. The electrochemical performance of the tubular cell was evaluated in N2/H2 gas at 750°C. The cell generated a maximum power density of 90 mW/cm2. The scanning electron microscope (SEM) micrographs after the electrochemical tests confirmed that the solvent-assisted lamination resulted in stable joining without delamination. Although the process and performance have yet to be optimized, the use of multilayer tape casting, solvent-assisted lamination, and co-firing is expected to make this method advantageous for low-cost mass production of tubular SOFCs.

A novel paper‐based biofuel cell with a series/parallel array structure has been fabricated, in which the cell voltage and output power can easily be adjusted as required by printing. The output of the fabricated 4‐series/4‐parallel biofuel cell reached 0.97±0.02 mW at 1.4 V, which is the highest output power reported to date for a paper‐based biofuel cell. This work contributes to the development of flexible, wearable energy storage device.

In this letter, we propose a textile metamaterial absorber that using screen printing technology. A unit cell of the proposed absorber is motivated from the commercial Chanel logo for wearable applications. The complex impedance of the designed unit cell is analyzed by full-wave simulation. To verify its performance, the proposed metamaterial absorber is fabricated where the silver conductive ink is screen printed on an ordinary textile. From experimental results, the absorptivity of the proposed absorber is almost perfect at 10.8 GHz under normal incidence. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1424–1427, 2017

Paper has been used for a long time in the production of low-cost point-of-care (POC) detection devices, most of which rely on the detection of colored bands by the user. However, test strips rarely provide the quantitative detection of biomarkers in clinical samples. In contrast, electrochemical detection enables quantitative detection in paper-based immunoassays. Here, we demonstrate the production of a simple and economical lateral-flow electrode device using only screen printing. Contrary to previous work, this device is used to simplify the washing and detection of a short and sensitive immunomagnetic assay for myeloperoxidase (MPO) detection. As we show, after incubation of the sample with magnetic beads (MBs) and detection antibody (Ab) for only 5 min, the whole reaction mixture can be directly pipetted onto the strip. Washing and detection can then be performed, as the MBs are retained with the aid of a magnet, and minimal user intervention is needed. The obtained results reveal that MPO can be detected in 1 : 100 diluted serum with limits of detection and quantification of 0.18 and 0.62 ng mL−1, respectively, in less than 15 min.

We have presented simplified industrial processes to fabricate high performance back-junction back-contact (BJBC) silicon solar cells. Good optical surface structures (solar averaged reflectance 2.5%) and high implied open-circuit voltage (0.695 V) have been realized in the BJBC cell precursors through wet chemical processing, co-diffusion, P ion implantation and annealing oxidation, as well as laser patterning and plasma enhanced chemical vapour deposition passivation processes. We have achieved a certified high efficiency of close to 22% on BJBC silicon solar cells with the size of 4.04 cm2 by using screen printing and co-firing technologies. The manufacturing process flow further successfully yields efficiency of around 21% BJBC silicon solar cells with enlarged sizes of 6 × 6 cm2. The present work has demonstrated that the commercialization of low-cost and high-efficiency BJBC solar cells is possible because we have used processes compatible with existing production lines. Copyright © 2017 John Wiley & Sons, Ltd.

Thiamine chloride hydrochloride (TCH) is one of the B-complex vitamins which resemble a very biologically important group of biomolecules. The first screen-printed graphite ion-selective sensor for the determination of TCH was prepared and characterized. The sensor is based on TCH-tetraphenylborate as electrode material. A number of parameters such as the type of solvent mediator, weight percent of the ion-exchanger, test solution temperature and possible interferences were extensively studied. Moreover, the surface morphology of the prepared sensor was studied using scanning electron microscopy. The sensor shows a Nernstian slope of 30.60±0.07 mV/decade, a low LOD of 5.08×10−6 mol/L and a wide applicability range of 5.96×10−6-1.00×10−2 mol/L. The sensing graphite ink remains usable for at least one month. Fast potentiometric response was obtained within 5 s and remains stable for at least 60 s. The sensor was applied to the analysis of TCH in pure solutions and multivitamin ampoules from the Egyptian market using the standard addition method and high recovery values of 97–102 % were obtained. Low %RSD values (0.27-1.30) indicate high precision of the proposed sensor. Our sensor provides the advantages of disposability, simple preparation procedures, sensitivity and easy storage and transportation.

Phosphor-in-glass (PiG) thick film was fabricated on a borosilicate glass substrate using a conventional screen printing method and employing phosphosilicate glass to allow low-temperature sintering. The vehicle content and sintering temperature were optimized to form a thick film with a thickness of ~50 μm. Commercial yellow (Y3Al5O12:Ce3+) and red (CaAlSiN3:Eu2+) phosphors were successfully incorporated within the glass matrix and then sintered at 550°C. Color-tunable white LEDs were achieved using the PiG thick films as a color converter by varying the glass to phosphor (GtP) ratio. The high luminous efficacy of up to ~120 lm/W and high color rendering index of up to 89 in combination with the thermal quenching property prove the practical feasibility of the PiG thick films for high-power/high-brightness LED applications.

A new synthesis of methacrylate end-capped Poly(3,4-ethylenedioxythiophene) (PEDOT) was performed: the polymer is soluble in common organic solvents, thus overcoming the well-known technical problems related to the use of commercial PEDOT in different printing technologies, such as screen printing, due to its poor processability and compatibility in formulations with other resins and polymers. The new synthetic method developed is based on the direct oxidative polycondensation of 3,4-ethylenedioxythiophene (EDOT) in the presence of an oxidant species and a cross-linkable end-capper, i.e. methacrylate end-capped EDOT (mEDOT), prepared via Friedel Crafts acylation with methacryloyl chloride. The oxidative polycondensation between EDOT and mEDOT monomers in the presence of a new kind of doping agent, Sulfonated Polyarylethersulfone (SPES)—characterized by different degree of sulfonation (DS)—was conducted, leading to functional end-capped conducting PEDOT (mPEDOT_SPES), with conductivity of 210 S/cm, 50 S/cm higher than the one of commercial PEDOT. Thanks to the enhancement of solubility, leading to better processability, end-capped PEDOTs were formulated with a thermoplastic ink, Plastisol®, and electronic circuits were successfully screen printed on flexible cotton substrates, to obtain printed cross-linkable electronic circuits. The conductive features of mPEDOT_SPESs were successfully compared with the ones of PEDOT and of not-doped end-capped PEDOTs. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

The adoption of neural interfacing into neurological diagnosis is severely hampered by the complex, costly, and error-prone manufacturing methods, requiring new fabrication processes and materials for flexible neural interfacing. Here a strategy for fabricating highly stretchable neural electrode arrays based on screen printing of liquid metal conductors onto polydimethylsiloxane substrates is presented. The screen-printed electrode arrays show a resolution of 50 µm, which is ideally applicable to neural interfaces. The integration of liquid metal-polymer conductor enables the neural electrode arrays to retain stable electrical properties and compliant mechanical performance under a significant (≈108%) strain. Taking advantage of its high biocompatibility, liquid metal electrode arrays exhibit excellent performance for neurite growth and long-term implantation. The stretchable electrode arrays can spontaneously conformally come in touch with the brain surface, and high-throughput electrocorticogram signals are recorded. Based on stretchable electrode arrays, real-time monitoring of epileptiform activities can be provided at different states of seizure. The method reported here offers a new fabrication strategy to manufacture stretchable neural electrodes, with additional potential utility in diagnostic brain-machine interfaces.

The future of mankind holds great promise for things like the Internet of Things, personal health monitoring systems, and smart cities. To achieve this ambitious goal, it is imperative for electronics to be wearable, environmentally sustainable, and safe. However, large-scale manufacture of self-sufficient electronic systems by exploiting multifunctional materials still faces significant hurdles. Herein, multitasking aqueous printable MXene inks are reported as an additive-free high-capacitance electrode, sensitive pressure-sensing material, highly conducting current collector, metal-free interconnector, and conductive binder. By directly screen printing MXene inks, MXene-based micro-supercapacitors (MSCs) and lithium-ion microbatteries (LIMBs) are delicately fabricated on various substrates. The as-prepared MSCs exhibit ultrahigh areal capacitance of 1.1 F cm-2 and the serially connected MSCs offer a record voltage of 60 V. The quasi-solid-state LIMBs deliver a robust areal energy density of 154 μWh cm-2 . Furthermore, an all-flexible self-powered integrated system on a single substrate based on the multitasking MXene inks is demonstrated through seamless integration of a tandem solar cell, the LIMB, and an MXene hydrogel pressure sensor. Notably, this integrated system is exceptionally sensitive to body movements with a fast response time of 35 ms. Therefore, this multipurpose MXene ink opens a new avenue for powering future smart appliances.

Carrier selective passivated contacts composed of thin oxide, n + polycrystalline Si and metal on top of a n-Si absorber can significantly lower the recombination current density (Jorear ≤8 fA/cm2) under the contact while providing excellent specific contact resistance (5–10 mΩ-cm2); 25.1% efficient small area cells with photolithography front contacts on boron doped selective emitter and Fz wafers have been achieved by Fraunhofer ISE using their tunnel oxide passivated contact (TOPCon) approach. This paper shows a methodology to model such passivated contact cells using Sentaurus device model, which involves replacing the TOPCon region by carrier selective electron and hole recombination velocities to match the measured Jorear of the TOPCon region as well as all the light IV values of the cell. We first validated the methodology by modeling a 24.9% reference cell. The model was then extended to assess the efficiency potential of large area TOPCon cells on commercial grade n-type Cz material with screen-printed front contacts. To use realistic input parameters, a 21% n-type PERT cell was fabricated on Cz wafer (5 Ω-cm, 1.5-ms lifetime). Modeling showed that the cell efficiency will improve to only 21.6% if the back of this cell is replaced by the above TOPCon, and the performance is limited by the homogenous emitter. Efficiency was then modeled to improve to 22.6% with the implementation of selective emitter (150/20 Ω/sq). Finally, it is shown that screen printing of 40-µm-wide lines and improved bulk material (10 Ω-cm, 3-ms lifetime) can raise the single side TOPCon Cz cell efficiency to 23.2%. Copyright © 2016 John Wiley & Sons, Ltd.