Enhanced field emission performance of gold nanoparticle decorated Bi₂S₃ nanoflowers

Au nanoparticles (NPs) are decorated on hydrothermally synthesized Bi₂S₃ nanorods (NRs) to enhance the field electron emission (FEE) performance as compared to bare Bi₂S₃ nanorods, resulting in reduction in turn-on field from 3.7 to 2.7 V μm^-1 (at the current density of 1.0 μA cm^-2) with significant increment in maximum emission current density from 138 to 604.8 μA cm^-2 (at a field of 7.8 V μm^-1) respectively. FESEM/TEM reveals that Bi₂S₃ nanoflowers are assembled from Bi₂S₃ NRs of a typical diameter of 120 ± 10 nm, and Au NPs of diameter about 5-10 nm are uniformly decorated onto the surface of NRs to form an Au/Bi₂S₃ composite. XRD analysis suggests that the as-synthesized product consists of orthorhombic Bi₂S₃ NRs decorated with face-centered cubic Au NPs. The XPS spectrum shows the elemental mapping of the as-synthesized Au/Bi₂S₃. Improvement in field emission properties is mainly attributed to a reduction in work function and increasing emitting sites due to Au NP decoration.