“Our work is a step towards being able to achieve parity in performance and material capabilities between such 3D electronics and conventional 2D electronics”Rajiv Malhotra

Researchers at Rutgers University in the US have embedded high-performance electrical interconnections inside 3D-printed structures made from polymers, in an advance that could lead to smaller, versatile and energy-efficient drones and better-performing unmanned small satellites, as well as transmitters, sensors, biomedical implants and smart structures. The innovation holds promise for the development of an integrated electronic unit based on 3D printing and intense pulses of light to fuse silver nanoparticles.

The study, which was described in the journal Additive Manufacturing [Jahanghir et al. Addit. Manuf. (2019) DOI: 10.1016/j.addma.2019.100886], was based on pulses of high-energy light that worked to fuse silver nanowires to produce circuits able to conduct 10 times more electricity than currently achievable. This increased conductivity helped to decrease energy use, and to potentially extend the life of devices and increase their performance. The process could also find applications in antennas, pressure sensors, electrical coils and electrical grids for electromagnetic shielding, and is easily compatible with commercially available 3D printing.

Combining metal nanoparticle printing and additive manufacturing has the potential for integrating 3D conductive elements and electronic devices inside objects, demonstrating the multilayer sensing of internal temperature and a light sensing circuit with embedded interconnects. The team employed intense pulsed light sintering from a xenon lamp to fuse the silver nanowires, showing they improved upon the nanospheres conventionally used, increased as-printed conductivity and accelerated sintering/fusion under the pulsed light. They found that, with the aid of the additive process for producing the polymer, the nanowires were able to efficiently enhance overall conductivity.

Although creating circuits inside 3D structures, and its potential for multifunctionality and miniaturization, has also previously been shown by others, this research was able to produce parts with a specific shape and structural property, and also with further electromechanical, thermal, chemical, optical and magnetic functionality that could benefit off-the-shelf devices. As senior author Rajiv Malhotra told Materials Today, “Our work is a step towards being able to achieve parity in performance and material capabilities between such 3D electronics and conventional 2D electronics”. Other applications that would profit from such increased light-weighting and maneuverability include medical assistive devices, smart polymers, and in communication and sensing.

The team now hope to produce high-performance electrical systems inside multimaterial 3D components that are not just rigid but also very flexible, and to improve their conductivity. It is thought the use of core-shell 2D nanoparticles and highly stretchable interconnects will increase conductivity even further while allowing for greater mechanical robustness.

Improved electrical devices from 3D-printed polymer structures