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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.
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Nozzle‐Free Printing of CNT Electronics Using Laser‐Generated Focused Ultrasound
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.
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- Award ID(s):
- 1825502
- PAR ID:
- 10505273
- Publisher / Repository:
- Wiley-VCH GmbH
- Date Published:
- Journal Name:
- Small Methods
- ISSN:
- 2366-9608
- Subject(s) / Keyword(s):
- Printed Electronics Nozzle-Free Additive Manufacturing
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/smtd.202301596
