Toward Multifunctional Metal Nanoclusters with NIR-II Photoluminescence

ConspectusThe second near-infrared optical window (NIR-II, 1000-1700 nm) represents a highly promising regime for optical imaging and biosensing, because of deep tissue penetration, minimal autofluorescence, and high spatiotemporal resolution in this regime. Among a diverse library of NIR-II luminescence materials, metal nanoclusters (NCs) stand out as particularly attractive options due to their unique properties, including subnanometer size, favorable biocompatibility, substantial Stokes shift, and adjustable photoluminescence (PL) characteristics. Our group has dedicated sustained efforts to developing cluster-based NIR-II PL materials, contributing to this field by proposing PL mechanisms, revealing the structure-PL correlation, providing PL tuning methods, and expanding the functions of luminescent metal NCs, which were summarized below. Furthermore, we look to the directions of future efforts in this active field.