# Three-dimensional printing of nanomaterials-based electronics with a metamaterial-inspired near-field electromagnetic structure

## TL;DR

This paper introduces a new 3D printing method using metamaterial-inspired microwave structures to selectively heat and print electronics with nanomaterials.

## Contribution

The novel use of metamaterial-inspired near-field electromagnetic structures enables selective and rapid in situ heating for 3D printing.

## Key findings

- Meta-NFS achieves spatial resolution and power density for printing freeform microstructures.
- The method allows local programming of electronic and mechanical properties within opaque materials.
- Near-field microwave 3D printing expands the range of materials compatible with 3D printing.

## Abstract

Three-dimensional (3D) printing can create freeform architectures and electronics with unprecedented versatility. However, the full potential of electronic 3D printing has so far been limited by the inability to selectively anneal the printed materials, especially on temperature-sensitive substrates. Here, we achieve highly selective and rapid volumetric heating of 3D-printed nanomaterials and polymers in situ by focusing microwaves using a metamaterial-inspired near-field electromagnetic structure (Meta-NFS). In contrast to previous work, the Meta-NFS achieves the spatial resolution and power density needed to 3D print freeform microstructures where the electronic and mechanical properties can be locally programmed even within optically opaque materials. By broadening the material palettes compatible with 3D printing, near-field microwave 3D printing with Meta-NFS enables classes of electronics that are otherwise challenging to create.

Near-field microwaves with Meta-NFS enable selective and rapid in situ heating of 3D-printed nanomaterials.