Progress, enhancement mechanisms and applications of electrochemiluminescence and photoluminescence metal nanoclusters

In recent years, luminescent metal nanoclusters (metal NCs) with the unique features of intriguing optical properties and excellent biocompatibility, have emerged as a promising emitter in photoluminescence and electrochemiluminescence biosensing and bioimaging field. Nevertheless, with ever-increasing demand for sensitivity and brightness, relatively low quantum yields of metal NCs limit their potential applications. Gaining a deeper understanding of structure-function relationship will guide the preparation of high-efficient luminescent metal NCs and advance their applications. In this review, delving into fundamental photoluminescence and electrochemiluminescence mechanism, we discuss the effect of ligand structure on luminescent properties of metal NCs. Furthermore, we summarize recent progress in high-efficient metal NCs as well as their sensing and imaging applications on photoluminescence and electrochemiluminescence in recent three years. More importantly, we envisage the challenges of metal NCs in future research, which will bring exciting opportunities for the tailor-made functional metal NCs for promising analytical applications.