Scalable Fabrication of Quasi-One-Dimensional van der Waals Ta₂Pt₃Se₈ Nanowire Thin Films via Solution Processing for NO₂ Gas Sensing over Large Areas

Solution-based processing of van der Waals (vdW) one- (1D) and two-dimensional (2D) materials is an effective strategy to obtain high-quality molecular chains or atomic sheets in a large area with scalability. In this work, quasi-1D vdW Ta₂Pt₃Se₈ was exfoliated via liquid phase exfoliation (LPE) to produce a stably dispersed Ta₂Pt₃Se₈ nanowire solution. In order to screen the optimal exfoliation solvent, nine different solvents were employed with different total surface tensions and polar/dispersive (P/D) component (P/D) ratios. The LPE behavior of Ta₂Pt₃Se₈ was elucidated by matching the P/D ratios between Ta₂Pt₃Se₈ and the applied solvent, resulting in N-methyl-2-pyrrolidone (NMP) as an optimal solvent owing to the well-matched total surface tension and P/D ratio. Subsequently, Ta₂Pt₃Se₈ nanowire thin films are manufactured via vacuum filtration using a Ta₂Pt₃Se₈/NMP dispersion. Then, gas sensing devices are fabricated onto the Ta₂Pt₃Se₈ nanowire thin films, and gas sensing property toward NO₂ is evaluated at various thin-film thicknesses. A 50 nm thick Ta₂Pt₃Se₈ thin-film device exhibited a percent response of 25.9% at room temperature and 32.4% at 100 °C, respectively. In addition, the device showed complete recovery within 14.1 min at room temperature and 3.5 min at 100 °C, respectively.