Inorganic 2D Luminescent Materials: Structure, Luminescence Modulation, and Applications

Inorganic luminescent semiconductors have triggered burgeoning research interest in all-solid-state light-emitting devices over the past decades owing to their band-to-band transitions along with their high efficiency and excellent long-term stability compared with most organic luminescent materials. Recent booming developments in 2D materials demonstrate their fascinating tunable layer-dependent electronic structures, strong light-matter interactions, high carrier mobilities, and broad spectral ranges at the 2D limit, which are promising for high-performance light-emitting devices. Here, state-of-the-art 2D luminescent nanomaterials are reviewed from the fundamental aspects of crystal structures and electronic properties to practical applications, providing insights into the luminescence mechanism. Many research paradigms are comprehensively discussed to elaborate ingenious luminescence modulation strategies through control of the microstructure, such as the number of layers, defects, morphologies, charge carriers, heterostructures, and surface states of 2D systems. Promising applications of 2D luminescent systems in light-emitting diodes, lasers, and bioimaging and biosensing devices are systematically illustrated. Finally, by summarizing the luminescence in 2D materials, challenges are proposed, which will provide new opportunities for developing 2D luminescence physics, luminescent materials, and related light-emitting device applications.