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

One-dimensional (1D) morphology-unique Au-AgS nano-hybrids are achieved by combining the interfacial self-assembly of Ag nanowires, interface-oriented site-specific etching of Ag nanowires with AuCl, and the sulfurization of S. The as-formed Au-AgS nano-hybrid has a trough-like morphology. The wall of the Au-AgS nanotrough is a AgS/Au/AgS trilayer wall, but the AgS layer is a AgS-rich mixture of AgS and Au rather than pure AgS because of the diffusion of Au atoms towards AgS. The Au-AgS 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 AgS. This enhanced PEC response originates from the localized plasmonic resonance effect of Au. Moreover, the PEC biosensor based on the Au-AgS 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 and a low detection limit of 0.67 pmol L. This study provides a new model for studying the PEC behavior of plasmonic metal/semiconductor materials, and this Au-AgS nanotrough may also be useful in the fields of photocatalysis and photovoltaics.