This is an example of simple light-sensing electronics with an LED, a light-sensitive diode, and power connected by a high-performance circuit inside a polymer. The LED is on when exposed to light and off when light from the diode is blocked. (Image: Md Naim Jahangir)

Rutgers engineers have embedded high performance electrical circuits inside 3D-printed plastics, which could lead to smaller and versatile drones and better-performing small satellites, biomedical implants, and smart structures.

They used pulses of high-energy light to fuse tiny silver wires, resulting in circuits that conduct 10 times more electricity than the state of the art, according to the engineers. That can reduce energy use, extend the life of devices, and increase their performance.

Embedding electrical interconnections inside 3D-printed structures made of polymers or plastics, can create new paradigms for devices that are smaller and more energy-efficient. Such devices could include CubeSats (small satellites), drones, transmitters, light and motion sensors, and Global Positioning Systems. Such interconnections are also often used in antennas, pressure sensors, electrical coils, and electrical grids for electromagnetic shielding.

The engineers used “intense pulsed light sintering” — using high-energy light from a xenon lamp — to fuse long thin rods of silver called nanowires. Nanomaterials are measured in nanometers (a nanometer is a millionth of a millimeter — about 100,000 times thinner than a human hair). Fused silver nanomaterials are already used as electrical conductors in devices such as solar cells, displays, and radio-frequency identification (RFID) tags.

According to the engineers, the next steps include making fully 3D internal circuits, enhancing their conductivity, and creating flexible circuits inside flexible 3D structures.