Signal amplified sandwich-type photoelectrochemical sensing assay based on rGO-Znln2S4 functionalized Au-WO3 IOPCs Z-scheme heterojunction

A novel photoelectrochemical (PEC) detection strategy based on reduced graphene oxide-Znln(2)S(4) (rGOZnln(2)S(4)) functionalized Au-WO3 inverse opal photonic crystals (IOPCs) Z-scheme photoresponse system was designed. Benefiting from great optical property of WO3 IOPCs, the optical absorption of PEC sensor was highly enhanced. Meanwhile, the 'Z-scheme' electron transfer between Znln(2)S(4) and WO3 IOPCs with application of Au nanoparticles (NPs) and rGO as electron mediators largely promoted separation of photo-generated carriers. Consequently, the enhanced optical absorption and accelerated photo-excited charge separation were beneficial to increase of photocurrent, resulting in an amplification of detection signal. The sandwich-type analytical mode was further applied to enhance the specificity and increase the sensitivity. Under optimum conditions, the PEC sensing system exhibited great property towards oxytetracycline (OTC) detection with a linear range of 2 x 10(-4) -1 x 10(-1) nM and a low detection limit of 1.2 x 10(-4) nM (approximate to 5.52 x 10(-2) ng L-1). Given these advantages, the developed PEC sensing strategy offers a new avenue for efficient detection of other targets. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

A novel PEC detection strategy based on rGOZnIn2S4 functionalized Au-WO3 inverse opal photonic crystals was designed to achieve high sensitivity detection of OTC using a Z-scheme photoresponse system.