Maskless Patterning of Biodegradable Conductors by Selective Laser Sintering of Microparticle Inks and Its...

Biodegradable electronic devices are able to break down into benign residues after their service life, which may effectively alleviate the environmental impacts as a consequence of the proliferation of consumer electronic technology. The widespread adaptation to biodegradable systems is currently impeded by the lack of economic fabrication techniques for functional devices. Here, a facile approach to generate a biodegradable conductor is developed based on selective laser sintering of zinc and iron microparticle ink. The sintering process is effective to convert naturally oxidized microparticles into interconnected conductors. Arbitrary conductive features are readily created over flexible biodegradable substrates under ambient conditions, which exhibits excellent conductivity (∼2 × 10⁶ S m^-1), low sheet resistance (∼0.64 Ω □ ^- 1), fine feature resolution (∼45 μm), and mechanical flexibility. The practical suitability is demonstrated by fabricating a miniaturized near-field communication tag with the dimension to mount on the fingernail. The methodology is further extended to create a metallic grid as a biodegradable transparent electrode with low sheet resistance (2.5 Ω □^-1) and high optical transmittance (96%), which is employed as an epidermal transparent heater for thermotherapy. Maskless patterning of biodegradable conductors may find a broad range of applications in environment friendly gadgets and implantable medical devices.