Printing rare-earth-free (REF) magnetic inks: synthesis, formulation, and device applications.

Additive manufacturing (AM) of magnetic materials has recently attracted increasing interest for various applications but is often limited by the high cost and supply chain risks of rare-earth-element (REE) magnetic precursors. Recent advances in nanomanufacturing have enabled the development of rare-earth-free (REF) magnetic materials, such as spinel ferrites, hexaferrites, MnAl, MnBi, Alnico, FePt, and iron oxides/nitrides, which offer promising alternatives for printing high-performance magnetic devices. This review provides a detailed overview of the latest developments in REF magnetic materials, covering both synthesis strategies of REF magnetic materials/nanomaterials and their integration into AM processes.

Hybrid Data-Driven Discovery of High-Performance Silver Selenide-Based Thermoelectric Composites.

Optimizing material compositions often enhances thermoelectric performances. However, the large selection of possible base elements and dopants results in a vast composition design space that is too large to systematically search using solely domain knowledge. To address this challenge, a hybrid data-driven strategy that integrates Bayesian optimization (BO) and Gaussian process regression (GPR) is proposed to optimize the composition of five elements (Ag, Se, S, Cu, and Te) in AgSe-based thermoelectric materials.

High-throughput printing of combinatorial materials from aerosols.

The development of new materials and their compositional and microstructural optimization are essential in regard to next-generation technologies such as clean energy and environmental sustainability. However, materials discovery and optimization have been a frustratingly slow process. The Edisonian trial-and-error process is time consuming and resource inefficient, particularly when contrasted with vast materials design spaces.

Printing thermoelectric inks toward next-generation energy and thermal devices.

The ability of thermoelectric (TE) materials to convert thermal energy to electricity and highlights them as a promising candidate for sustainable energy applications. Despite considerable increases in the figure of merit of thermoelectric materials in the past two decades, there is still a prominent need to develop scalable synthesis and flexible manufacturing processes to convert high-efficiency materials into high-performance devices. Scalable printing techniques provide a versatile solution to not only fabricate both inorganic and organic TE materials with fine control over the compositions and microstructures, but also manufacture thermoelectric devices with optimized geometric and structural designs that lead to improved efficiency and system-level performances.

Atmospheric Pressure and Ambient Temperature Plasma Jet Sintering of Aerosol Jet Printed Silver Nanoparticles.

Atmospheric pressure nonthermal plasmas hold great promise for applications in environmental control, energy conversion, and material processing. Even at room temperature, nonthermal plasmas produce energetic and reactive species that can initiate surface modifications at a plasma-surface interface, including thin-film nanoparticle assemblies, in a nondestructive and effective way. Here, we present the plasma-activated sintering of aerosol jet printed silver thin films on substrates ranging from glass to delicate materials including blotting paper, fruits, and flexible plastic.

Electrically conductive 3D printed TiCT MXene-PEG composite constructs for cardiac tissue engineering.

Tissue engineered cardiac patches have great potential as a therapeutic treatment for myocardial infarction (MI). However, for successful integration with the native tissue and proper function of the cells comprising the patch, it is crucial for these patches to mimic the ordered structure of the native extracellular matrix and the electroconductivity of the human heart. In this study, a new composite construct that can provide both conductive and topographical cues for human induced pluripotent stem cell derived cardiomyocytes (iCMs) is developed for cardiac tissue engineering applications.

Colloidal Nanosurfactants for 3D Conformal Printing of 2D van der Waals Materials.

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.

3D Printing of Solution-Processable 2D Nanoplates and 1D Nanorods for Flexible Thermoelectrics with Ultrahigh Power Factor at Low-Medium Temperatures.

Solution-processable semiconducting 2D nanoplates and 1D nanorods are attractive building blocks for diverse technologies, including thermoelectrics, optoelectronics, and electronics. However, transforming colloidal nanoparticles into high-performance and flexible devices remains a challenge. For example, flexible films prepared by solution-processed semiconducting nanocrystals are typically plagued by poor thermoelectric and electrical transport properties.

High thermal conductivity through simultaneously aligned polyethylene lamellae and graphene nanoplatelets.

The effect of simultaneous alignment of polyethylene (PE) lamellae and graphene nanoplatelets (GnP) on the thermal conductivity (k) of PE-GnP composites is investigated. Measurements reveal a large increase of 1100% in k of the aligned PE-GnP composite using 10 wt% GnPs relative to unoriented pure PE. The rate of increase of k with applied strain for the pure PE-GnP composite with 10 wt% GnP is found to be almost a factor of two higher than the pure PE sample, pointing to the beneficial effect of GnP alignment on k enhancement.