Rational design an oval heterostructure and tight linking interface of ZnS@CdS(3) for sensitively photoelectrochemical bioanalysis of PSA

Abstract

Photoactive material with heterostructures could be effectively employed to promote the photoelectrochemical (PEC) property. Herein, two species heterostructured ZnS@CdS(1−2) composites derived from ZIF-8-S MOFs via a sulfofication reaction in situ using Cd(NO3)2, CdC12 cadmium reagents, and further gained the oval ZnS@CdS(3) after annealing the ZnS@CdS(2). Under irradiation, the PEC results showed that the photocurrent response of ZnS@CdS(3) signally enhanced compared to disordered heterostructures of ZnS@CdS(1), ZnS@CdS(2) and pure ZnS or CdS. It was ascribed to the staggered levels based on matching band-gap to form type II heterojunction of ZnS@CdS(3) could facilitate photo-induced electron/hole (e-/h+) separation and transfer. The obtained photoelectric material with a tight connecting interface also could reduce the carriers transport distance. Besides, the structured and well-distributed ZnS@CdS(3) was beneficial to improve synergistic effect on every component, which resulting in violently photocurrent output. This ZnS@CdS(3) modified ITO electrode to create the PEC biosensor (BSA/anti-PSA/ZnS@CdS(3)/ITO) had been successfully applied for the PSA detection with a wide linear range of 0.001 ∼ 150 ng mL−1 and ultralow detection limit of 0.27 pg mL−1. This research innovatively designed a close contact heterojunction interface with superior PEC nature for biosensor preparations.