Layered superlattices: from physical assembly to chemical synthesis and emerging applications.

Quantum materials offer a powerful platform for exploring emergent condensed matter phenomena and developing functional devices, owing to their tunable electronic structures, quasiparticle excitations and collective quantum effects. Layered superlattices are a class of layered heterostructures formed by the periodic stacking of two or more sublattices along the direction perpendicular to the layers, with the constituent layers differing in composition, structure, or electronic properties. Such structural versatility establishes layered superlattices as a materials platform for connecting emergent quantum states with functional implementation. This review systematically summarizes the classification of sublattices in layered superlattices, including systems composed of inorganic sublattices and hybrid architectures comprising organic components and coordination-complex building blocks. It then discusses the major fabrication strategies, ranging from physical assembly to chemical synthesis, with an emphasis on the material compatibility, structural controllability and scalability of each approach. The review examines how quantum confinement, resonant tunneling, interlayer coupling and cooperative interfacial effects govern emergent physical properties and device performance. Recent progress in superconductivity, thermoelectrics, optoelectronic detection, sensing, and energy storage and conversion is also summarized. Finally, this review discusses key challenges in structural control, scalable synthesis, stability improvement, dynamic characterization and nonequilibrium photophysics, while highlighting future opportunities enabled by machine learning, high-throughput experimentation, multiscale simulations and advanced characterization. Layered superlattices are poised to accelerate the transition of quantum materials from structural design to functional integration and to provide a materials foundation for future electronic, optoelectronic and energy technologies.