Tungsten oxide nanoparticle and aggregate formation through direct femtosecond laser ablation in air

Abstract

In this work, we report the generation of tungsten oxide (WO3) nanoparticles and aggregate structures through direct femtosecond laser ablation in air. The nanoparticle morphology is studied utilizing Raman spectroscopy and TEM analysis, showing the generation of nanorods in the monoclinic phase with an average width and length of 70 and 168 nm, respectively. A range of laser fluences (0.8 to 4.2 J/cm 2) were during the ablation process, demonstrating control over the spread and density of the aggregate structures. Moreover, through variation of the laser spot size we demonstrate controlled aggregate formation, creating structures ranging from a high-density web-like structure with high area coverage to longer wire-like structures with lengths above 100μm.