Near‐Infrared Carbon Dots: From Precursors and Synthesis to Luminescence Mechanisms and Multifunctional Applications

Abstract

ABSTRACT Carbon dots (CDs) are emerging zero‐dimensional carbon‐based nanomaterials with unique optical properties. Among them, near‐infrared carbon dots (NIR‐CDs), exhibiting absorption/emission in the biological transparency window (650‐1700 nm), have attracted increasing attention due to their excellent biocompatibility, high spatial resolution, and low photo‐toxicity. In this review, we systematically summarize the development of NIR‐CDs including preparation methods, rational design and choice of precursors, optical characteristics and mechanisms, and multifunctional applications. A comprehensive and detailed methodological description encompassing the synthesis strategies, rational design, and precursor engineering of NIR‐CDs are provided. And then the optical properties of NIR‐CDs, including absorption, fluorescence, phosphorescence, nonlinear optical properties, and their mechanisms are further discussed and analyzed. Finally, recent advances in the multifunctional applications of NIR‐CDs are summarized, covering light‐emitting devices, fluorescence sensing, environmental, hydrogen energy, and biomedical fields. By consolidating current knowledge into a unified framework and identifying key challenges and opportunities, the review not only offers the most up‐to‐date and holistic perspective on NIR‐CDs but also serves as a guide to accelerate the translation of NIR‐CDs from laboratory research to practical applications.