Design strategies, luminescence mechanisms, and solid-state lighting applications of lanthanide-doped phosphorescent materials

Nanomaterials have emerged as an active area of research. This is because of their broad spectrum of applications such as sensors, white light emitting diodes (LEDs), electronic displays, and other optoelectronic devices in the optics and electronic industries owing to their size- and shape-dependent properties. The synthesis technique plays a crucial role in tuning the size and shape of the materials. Herein, we briefly describe these nanomaterials' fundamental aspects, properties, and applications. Various nanomaterial synthesis methods are discussed. Their advantages and disadvantages are highlighted in conjunction with the criteria for selecting a synthesis method. The principle underlying the sonochemical method and its applicability in synthesizing diverse sub-15 nm size nanoparticles (NPs) are presented. The main objective of this article is to review recent studies on lanthanide-doped nanophosphors and the various parameters that play key roles in achieving optimum luminescence emission. Both down-conversion and up-conversion mechanisms are discussed. The importance of the combinations and concentrations of the synthesizer/activator, color tuning, and host material are emphasized.