An official website of the United States government
Abstract Screen printing provides a high throughput fabrication approach for flexible electronics. While PEDOT: PSS is widely adopted for the fabrication of flexible electronics due to its mechanical flexibility, electrical conductivity, and optical transparency, its intrinsic fluidic properties pose challenges for scale-up fabrication in high-performance applications. In this work, we develop a screen-printable and eco-friendly PEDOT:PSS/graphene composite ink to enable cost-effective and scalable screen printing of flexible devices. The ink formulation comprises a biodegradable binder and a green solvent without toxic surfactants, which enables a green printing process. The ink formulation is determined through comprehensive electrical and mechanical characterization to balance ink screen-printability and electrical properties. By screen-printing, the conductive PEDOT: PSS/ Graphene patterns are printed onto a wide range substrates, such as polyimide, polydimethylsiloxane, polyurethane, glass, and paper. The printed circuits demonstrate excellent flexibility, maintaining stable electrical responses over hundreds of bending cycles at a small bending radius. Using the formulated PEDOT: PSS/graphene ink, we successfully fabricate a flexible temperature sensor and flexible organic thin film transistor circuits to demonstrate its promising potential for the large-scale production of flexible wearable electronics.
more »
« less
This content will become publicly available on December 1, 2026
Experimental Assessment and Data-Driven Modeling of Three-Dimensional-Printed Conductive Patterns on Electrospun Substrates
Abstract Flexible electronics (FE) have emerged as a key technology with applications in various fields, e.g., energy storage and bio-electronics. Electrospinning (ES), inkjet printing (IJP), and intense pulsed light (IPL), constitute a flexible multistage system capable to handle high customization requirements. The ES/IJP/IPL system is used for flexible substrate fabrication, conductive patterns printing, and sintering, respectively. Although the ES/IJP/IPL system seems to be suitable for on-demand FE devices manufacturing, the correlation of materials and process parameters of individual stages (i.e., ES/IJP/IPL) with the FE devices performance (i.e., conductivity) remains unexplored. Therefore, the objective of this paper is to evaluate the integration of ES, IJP, and IPL, for future production of high-performance FE devices. Various materials and process parameters are used to investigate their influence on the FE device resistivity, including different polyacrylonitrile (PAN) concentrations, voltage regimes, flow rates and the collector types in ES, and distinct number of ink layers in IJP. The study includes (1) an experimental assessment of the electrospun membrane morphology (e.g., fiber diameter) and ink coating characteristics (e.g., ink penetration) using scanning electron microscopy (SEM), and (2) a data-driven analysis through logistic regression (LR), Gaussian process (GP), and Bayesian neural network (BNN) classification models to predict FE conductive feasibility. The results indicate that membranes with larger fiber diameters benefit ink penetration, printed layer/multilayer consistency, and conductivity. This is corroborated with the classification models, where the number of printed layers, fiber diameter, and collector type, are identified as significant factors for accurately predicting conductive patterns feasibility.
more »
« less
- Award ID(s):
- 2347497
- PAR ID:
- 10670822
- Publisher / Repository:
- The American Society of Mechanical Engineers
- Date Published:
- Journal Name:
- Journal of Micro and Nano Science and Engineering
- Volume:
- 13
- Issue:
- 4
- ISSN:
- 2994-7316
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Printed electronics have made remarkable progress in recent years and inkjet printing (IJP) has emerged as one of the leading methods for fabricating printed electronic devices. However, challenges such as nozzle clogging, and strict ink formulation constraints have limited their widespread use. To address this issue, a novel nozzle‐free printing technology is explored, which is enabled by laser‐generated focused ultrasound, as a potential alternative printing modality called Shock‐wave Jet Printing (SJP). Specifically, the performance of SJP‐printed and IJP‐printed bottom‐gated carbon nanotube (CNT) thin film transistors (TFTs) is compared. While IJP required ten print passes to achieve fully functional devices with channel dimensions ranging from tens to hundreds of micrometers, SJP achieved comparable performance with just a single pass. For optimized devices, SJP demonstrated six times higher maximum mobility than IJP‐printed devices. Furthermore, the advantages of nozzle‐free printing are evident, as SJP successfully printed stored and unsonicated inks, delivering moderate electrical performance, whereas IJP suffered from nozzle clogging due to CNT agglomeration. Moreover, SJP can print significantly longer CNTs, spanning the entire range of tube lengths of commercially available CNT ink. The findings from this study contribute to the advancement of nanomaterial printing, ink formulation, and the development of cost‐effective printable electronics.more » « less
-
null (Ed.)Graphene has proven to be useful in biosensing applications. However, one of the main hurdles with printed graphene-based electrodes is achieving repeatable electrochemical performance from one printed electrode to another. We have developed a consistent fabrication process to control the sheet resistance of inkjet-printed graphene electrodes, thereby accomplishing repeatable electrochemical performance. Herein, we investigated the electrochemical properties of multilayered graphene (MLG) electrodes fully inkjet-printed (IJP) on flexible Kapton substrates. The electrodes were fabricated by inkjet printing three materials – (1) a conductive silver ink for electrical contact, (2) an insulating dielectric ink, and (3) MLG ink as the sensing material. The selected materials and fabrication methods provided great control over the ink rheology and material deposition, which enabled stable and repeatable electrochemical response: bending tests revealed the electrochemical behavior of these sensors remained consistent over 1000 bend cycles. Due to the abundance of structural defects ( e.g. , edge defects) present in the exfoliated graphene platelets, cyclic voltammetry (CV) of the graphene electrodes showed good electron transfer ( k = 1.125 × 10 −2 cm s −1 ) with a detection limit (0.01 mM) for the ferric/ferrocyanide redox couple, [Fe(CN) 6 ] −3/−4 , which is comparable or superior to modified graphene or graphene oxide-based sensors. Additionally, the potentiometric response of the electrodes displayed good sensitivity over the pH range of 4–10. Moreover, a fully IJP three-electrode device (MLG, platinum, and Ag/AgCl) also showed quasi-reversibility compared to a single IJP MLG electrode device. These findings demonstrate significant promise for scalable fabrication of a flexible, low cost, and fully-IJP wearable sensor system needed for space, military, and commercial biosensing applications.more » « less
-
Birringer, Marc (Ed.)Abstract Over the past several years, atomically thin two‐dimensional carbides, nitrides, and carbonitrides, otherwise known asMXenes, have been expanded into over fifty material candidates that are experimentally produced, and over one hundred fifty more candidates that have been theoretically predicted. They have demonstrated transformative properties such as metallic‐type electrical conductivities, optical properties such as plasmonics and optical nonlinearity, and key surface properties such as hydrophilicity, and unique surface chemistry. In terms of their applications, they are poised to transform technological areas such as energy storage, electromagnetic shielding, electronics, photonics, optoelectronics, sensing, and bioelectronics. One of the most promising aspects ofMXene'sfuture application in all the above areas of interest, we believe, is reliably developing their flexible and bendable electronics and optoelectronics by printing methods (henceforth, termed asprinted flexible MXetronics). Designing and manipulatingMXeneconductive inks according to the application requirements will therefore be a transformative goal for future printed flexible MXetronics.MXene'scombined property of high electrical conductivity and water‐friendly nature to easily disperse its micro/nano‐flakes in an aqueous medium without any binder paves the way for designing additive‐free highly conductiveMXene ink. However, the chemical and/or structural and hence functional stability of water basedMXeneinks over time is not reliable, opening research avenues for further development of stable and conductiveMXeneinks. Such priorities will enable applications requiring high‐resolution and highly reliable printedMXeneelectronics using state‐of‐the art printing methods. EngineeringMXenestructural and surface functional properties while tuningMXeneink rheology in benign solvents of choice will be a key for ink developments. This review article summarizes the present status and prospects ofMXeneinks and their use in inkjet‐printed (IJP) technology for future flexible and bendableMXetronics.more » « less
-
Screen printing is a promising route towards high throughput printed electronics. Currently, the preparation of nanomaterial based conductive inks involves complex formulations with often toxic surfactants in the ink's composition, making them unsuitable as an eco-friendly printing technology. This work reports the development of a silver nanowire (AgNW) ink with a relatively low conductive particle loading of 7 wt%. The AgNW ink involves simple formulation and comprises a biodegradable binder and a green solvent with no toxic surfactants in the ink formulation, making it an eco-friendly printing process. The formulated ink is suitable for printing on a diverse range of substrates such as polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyimide (PI) tape, glass, and textiles. By tailoring the rheological behaviour of the ink and developing a one-step post-printing process, a minimum feature size of 50 μm and conductivity as high as 6.70 × 10 6 S m −1 was achieved. Use of a lower annealing temperature of 150 °C makes the process suitable for plastic substrates. A flexible textile heater and a wearable hydration sensor were fabricated using the reported AgNW ink to demonstrate its potential for wearable electronic applications.more » « less
