Selective metallization of polymer based on nanoscale tungsten oxide laser activators for advanced electronics

Abstract

In recent years, laser-induced selective metallization (LISM) has been widely used to fabricate complex metal patterns and circuits due to its superior precision. Laser sensitizers known as laser-activated for electroless copper plating (ECP) are a significant premise in LISM. Herein, we confirmed that tungsten oxides (WO2.72, WO2.92, and WO3) exhibited excellent LISM activity due to oxygen vacancies (OVs) in their lattice. Moreover, non-stoichiometric tungsten (WO2.72, WO2.92) presented higher activity due to a higher concentration of OVs than the stoichiometric form of WO3, indicating the importance of OVs to the activity of laser sensitizers in LISM. Moreover, a higher OVs concentration in the laser sensitizer resulted in a higher LISM activity. This finding points out the direction for future laser sensitizer screening, synthesis, and development. After 30 min ECP, the square resistance of the prepared copper layer on ABS/WO2.72, ABS/WO2.92, and ABS/WO3 are 0.014, 0.035, and 0.176 Ω/sq, respectively. The nanoscale tungsten oxides with excellent LISM activity enabled the rapid fabrication of metal patterns and circuits in various scenarios, which expands the research field and application prospect of LISM technology. We demonstrate the advantages of LISM with tungsten oxides in fabricating advanced electronics. A strategy for replacing hand-wound windings in electromagnetic generators with 2D on-chip planar inductor arrays from LISM was proposed. The generated current reached a high level of 193 mA, and can be directly connected to wireless sensor networks to supply power. This work is the first research ever reporting laser sensitizers of tungsten oxides and introducing LISM technology into self-powered electronics.