Engineering one-dimensional trough-like Au-Ag2S nano-hybrids for plasmon-enhanced photoelectrodetection of human α-thrombin.

Abstract

One-dimensional (1D) morphology-unique Au-Ag2S nano-hybrids are achieved by combining the interfacial self-assembly of Ag nanowires, interface-oriented site-specific etching of Ag nanowires with AuCl4-, and the sulfurization of S2-. The as-formed Au-Ag2S nano-hybrid has a trough-like morphology. The wall of the Au-Ag2S nanotrough is a Ag2S/Au/Ag2S trilayer wall, but the Ag2S layer is a Ag2S-rich mixture of Ag2S and Au rather than pure Ag2S because of the diffusion of Au atoms towards Ag2S. The Au-Ag2S nanotrough shows strong absorption in the visible region (400-800 nm) and exhibits a favorable photoelectrochemical (PEC) response, the photocurrent of which is ∼8.5 times larger than that of pure Ag2S. This enhanced PEC response originates from the localized plasmonic resonance effect of Au. Moreover, the PEC biosensor based on the Au-Ag2S nanotroughs shows high sensitivity and selectivity, satisfactory reproducibility, and good stability towards human α-thrombin (TB) detection: a sensitive linear response ranging from 1.00 to 10.00 pmol L-1 and a low detection limit of 0.67 pmol L-1. This study provides a new model for studying the PEC behavior of plasmonic metal/semiconductor materials, and this Au-Ag2S nanotrough may also be useful in the fields of photocatalysis and photovoltaics.