Different Synthesis Methods of Persistent Luminescence Nanoparticles

This chapter demonstrates the synthesis of various morphologies of persistent luminescence nanoparticles (PLNPs) and their composites using chemical and physical methods for a range of applications such as electroluminescent displays, solid-state lighting, lamp phosphors, thermoluminescent dosimeters, scintillation, etc. In contemporary material science research, the first stage of synthesizing various composites with different morphology of PLNPs is challenging. Particularly, this chapter concentrates on the synthesis of the different morphology of aluminate PLPNs. The divalent metal (M) and trivalent rare-earth (Ln) aluminates exist in different forms, of which MAl2O4 and LnAlO3 are the most widely used and studied due to their persistent luminescence. While synthesizing the PLNPs, many factors need to be considered, including the desired phase, the desired site of incorporation of the activator, specific grain size, and morphology for the desired application. Further, it is also important to consider the manufacturing cost, scalability, repeatability, reproducibility, and so forth. Different synthesis techniques are available to encounter the above difficulties, which are classified into two types: bottom-up approach and top-down approach. The bottom-up approach is the chemical method, which includes solution combustion, sol–gel, hydro/salvo thermal, and coprecipitation synthesis methods. Similarly, the top-down approach is the physical method, which includes high-energy ball milling, pulsed laser ablation, spray pyrolysis, and solid-state diffusion strategies which are the most important. Hence, these strategies are detailed in-depth with their advantages and limitations in the chapter. The chemical methods of synthesis of these aluminates based PLNPs are more advantageous over the physical approach to tuning the luminescence properties by tuning the morphology of the nanoparticles, incorporation of favorable impurities and/or defects for the PLNPs and, importantly, more homogenous chemical composition, where luminescence properties can be tuned to the desired extent.