Enhanced photoluminescence properties of bismuth sulfide nanocrystals with core-shell Ag@SiO₂

A novel self-assembled hybrid nanocompound consisting of bismuth sulfide nanocrystals (Bi₂S₃ NCs) and Ag@SiO₂ nanoparticles (NPs) is used to study the enhancement of photoluminescence by localized surface plasmon resonance (LSPR). Ag@SiO₂ core-shell NPs were prepared by deposition of silica onto the surface of Ag NPs through the sol-gel method and followed by surface modification via 3-aminopropyltriethoxysilane for the coming conjugation with Bi₂S₃ NCs. We propose the photoluminescence enhancement by the LSPR effect through adjusting the thickness of silica shell and the Ag@SiO₂ NP concentration. By modulating the thickness of the silica shell and the concentration of Ag NPs, the maximum enhancement of a 5.7 fold can be reached with the thickness of an SiO₂ shell at 22.5 nm. A clear red shift of the emission peaks in the Bi₂S₃ NCs-Ag@SiO₂ NPs hybrid structures is observed. Such a metal-enhanced Bi₂S₃ quantum dot (QD) fluorescence system may have promising applications in optoelectronic device.