Colloidal nanoparticles have been widely studied and proven to have unique and superior properties compared to their bulk form and are attractive building blocks for diverse technologies, including energy conversion and storage, sensing, electronics, etc. However, transforming colloidal nanoparticles into functional devices while translating their unique properties from the nanoscale to the macroscale remains a major challenge. The development of advanced manufacturing methodologies that can convert functional nanomaterials into high-performance devices in a scalable, controllable and affordable manner presents great research opportunities and challenges for the next several decades. One promising approach to fabricate functional devices from nanoscale building blocks is additive manufacturing, such as 2D and 3D printing, owing to their capability of fast prototyping and versatile fabrication. Here, we review recent progress and methodologies for printing functional devices using colloidal nanoparticle inks with an emphasis on 2D nanomaterial-based inks. This review provides a comprehensive overview on four important and interconnected topics, including nanoparticle synthesis, ink formulation, printing methods, and device applications. New research opportunities as well as future directions are also discussed. 
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                            Colloidal Nanosurfactants for 3D Conformal Printing of 2D van der Waals Materials
                        
                    
    
            Abstract Printing techniques using nanomaterials have emerged as a versatile tool for fast prototyping and potentially large‐scale manufacturing of functional devices. Surfactants play a significant role in many printing processes due to their ability to reduce interfacial tension between ink solvents and nanoparticles and thus improve ink colloidal stability. Here, a colloidal graphene quantum dot (GQD)‐based nanosurfactant is reported to stabilize various types of 2D materials in aqueous inks. In particular, a graphene ink with superior colloidal stability is demonstrated by GQD nanosurfactants via the π–π stacking interaction, leading to the printing of multiple high‐resolution patterns on various substrates using a single printing pass. It is found that nanosurfactants can significantly improve the mechanical stability of the printed graphene films compared with those of conventional molecular surfactant, as evidenced by 100 taping, 100 scratching, and 1000 bending cycles. Additionally, the printed composite film exhibits improved photoconductance using UV light with 400 nm wavelength, arising from excitation across the nanosurfactant bandgap. Taking advantage of the 3D conformal aerosol jet printing technique, a series of UV sensors of heterogeneous structures are directly printed on 2D flat and 3D spherical substrates, demonstrating the potential of manufacturing geometrically versatile devices based on nanosurfactant inks. 
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                            - Award ID(s):
- 1747685
- PAR ID:
- 10374722
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 32
- Issue:
- 39
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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