Innovative synthesis of Sb2O3@Ag core-shell nanoparticles by two-step laser ablation in liquid for photodetector applications.

In this study, a novel metal-semiconductor core-shell nanostructure (Sb2O3@Ag) was prepared via a facile two-step pulsed laser ablation in liquid (PLAL) technique considering different laser fluences. The microstructural analysis revealed a crystalline orthorhombic Sb2O3 structure, along with a face-centered-cubic phase for Ag nanoparticles; a reduction in the optical band gap from 3.05 eV to 2.82 eV was achieved when the laser fluence was decreased from 6.37 J cm-2 to 1.27 J cm-2, respectively. The corresponding photodetector, attained at 6.37 J cm-2, demonstrated a responsivity value of 113 mA W-1, along with a specific detectivity of 3.29 × 1010 Jones; these values were attained at an incident light intensity of 2 mW cm-2. In contrast, the addressed figures of merit decreased as the incident light intensity increased, with values reaching 22.9 mA W-1 and 6.63 × 109 Jones at 36 mW cm-2 (R λ ∝ P -1). The optimum device delivered rapid and sharp time-resolved characteristics with response/recovery times of 0.24/0.39 s, and other devices demonstrated relatively higher response/recovery times. This indicates faster electron injection than recombination for the optimum photodetector.