p-Type Dopant-Mediated Electron–Hole Recombineering to Tune the Electrochemiluminescence of Metal–Organic Frameworks

Abstract

Constructing high-performance electrochemiluminescence (ECL) emitters through rational structural engineering is pivotal to overcoming the intrinsic limitations of conventional systems and advancing their practical applications. This work reports an electron–hole recombination engineering strategy to enhance the ECL emission of metal–organic frameworks (MOFs) by p-type doping of metal single-atom sites. Using Zr-TBAPy as a model, the experimental data and theoretical calculations demonstrate that the doping of single-atom Au induces notable defect energy levels, thereby providing additional recombination channels for conduction-band (CB) electrons and valence-band (VB) holes. The defect level ultimately increases the electron–hole recombination efficiency. Compared to Zr-TBAPy, single-atom Au-doped Zr-TBAPy (Au@Zr-TBAPy) exhibits a 4-fold enhancement in cathodic ECL intensity with an ECL efficiency of up to 50.56%. An ECL immunoassay was used to demonstrate the ECL application of Au@Zr-TBAPy. This work not only proposes a rational metal single-atom doping strategy for engineering ECL emitters to achieve high performance but also provides fundamental insights into the dependence of ECL emission on metal single-atom sites, opening new avenues for advanced applications of MOFs in sensitive ECL biosensing.