From layered perovskite oxides to multifunctional devices: Recent progress in 2D niobate perovskites for photonics, catalysis, and beyond

Over the past decade, the library of two-dimensional (2D) niobate perovskites has been significantly expanded, featuring a wide array of intriguing properties such as exceptionally large specific surface area, outstanding flexibility and transparency, high chemical stability, and unique physical characteristics (including dielectric, ferroelectric, and semiconducting behaviors). The huge possibility to achieve controllable nanosheet characteristics such as composition, size, shape, and thickness by modifying the layered parent compound and the following exfoliation technique presents vast opportunities for achieving tunable functional properties. Additionally, the unique nature of 2D niobate perovskites have made them promising material candidates for multifunctional applications, such as photodetectors, phototransistors, photocatalysis, dielectric applications, etc. This review provides a concise overview of recent developments in the research on 2D niobate perovskites exfoliated from layered perovskite oxides, with emphasis on their microstructural, optical, dielectric and semiconducting properties. This review also explores the use of these materials in diverse applications, including microcapacitors, phototransistors, photodetectors, photocatalysis, and as functional elements in luminescence, nanofiltration, anticorrosion, template-assisted film growth, and more. Finally, we provide a perspective into material design and property regulation for widespread applications, highlighting the challenges associated with these efforts.