Self-Limited Ultraviolet Laser Sintering of Liquid Metal Nanoparticles for Ultrathin, Flexible Electromagnetic Functional Device

Abstract

Pulsed laser sintering of liquid metal nanoparticles (LMNPs) has drawn increasing attention owing to its potential in direct fabricating of high-resolution patterns or conductive films on flexible substrates. Herein, we present a facile approach to rapidly fabricate sintered LMNPs film in combination spray-printing with direct nanosecond ultraviolet (UV) laser sintering. The thickness of as-prepared conductor could be as low as ~2 μm, and their sheet resistance are easily tuned at least seven orders of magnitude with laser parameters. A calculated parametric map upon particle diameter and laser fluence whether or not a LMNP is ruptured has been summarized and it is well in accordance to the experiment results. And stacked model has been established to figure out the limited sintering depth of UV laser by calculation of the distinct maximum temperature distributions among the layers. Such laser-sintered LMNPs films are adopted to fabricate flexible electromagnetic interference shielding (EMI SE) films with superior EMI shielding effectiveness of ~33 dB and SSE/t of ~27500 dB•cm 2 •g -1 and flexible electromagnetic metamaterials with a high absorption of ＞99.9% at resonance frequency of 12.9 GHz and 14.3 GHz, showing their potential for high-performance flexible EMI shielding and electromagnetic wave absorption applications.

Keywords: Liquid metal nanoparticles, UV laser sintering, Localized surface plasmon resonance, Electromagnetic interference shielding, Metamaterials.