Two-dimensional black phosphorus nanoflakes: A coreactant-free electrochemiluminescence luminophors for selective Pb2+ detection based on resonance energy transfer

As a nondegradable environmental pollutant, lead ion (Pb2+) has been proven to be deleterious for environmental and health. Conveniently, quickly and accurately on-site detection of Pb2+ is of paramount importance. Herein, an electrochemiluminescence (ECL) assay protocol using two-dimensional black phosphorus (2D BP) nanoflakes as new ECL emitter for highly sensitive and selective trace Pb2+ was designed on the basis of Pb2+ induced ECL resonance energy transfer (ECL-RET) between 2D BP nanoflakes and Ag/AgCl nanocubes. Anodic green ECL emission of BP nanoflakes without any coreactants was achieved. It is noteworthy that the possible ECL mechanism and the influence of coreactants on the ECL behaviour of BP nanoflakes were further investigated. Benefitting from the well match between the ECL emission spectrum of BP nanoflakes (similar to 510 nm) and the absorption spectrum of Ag/AgCl nanocubes (200-300 nm and 400-700 nm), effective energy transfer yielded. The introduction of Pb2+ would lead to the detachment of Ag/AgCl nanocubes then result in an enhanced ECL emission. Based on this, the proposed method could accurately quantify the Pb2+ in the range from 0.5 pM to 5 nM, which exhibited comparative performance to previous work. Furthermore, this study presents the example of employing 2D BP nanoflakes as ECL emitters and constructing a coreactant-free ECL sensing platform, which might open up a promising route for the potential design and implement in clinical analysis.

Automated summary

This study developed a new electrochemiluminescence assay method using two-dimensional black phosphorus nanoflakes for highly sensitive and selective detection of trace lead ions. The method demonstrated effective energy transfer between the BP nanoflakes and Ag/AgCl nanocubes, resulting in enhanced ECL emission in the presence of lead ions. This approach could accurately quantify lead ions in a range from 0.5 pM to 5 nM and presents a promising route for potential applications in clinical analysis.