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.