Defect-Modulated Trap Engineering of Long Persistent and Mechanoluminescence Phosphors for Advanced Applications

Defects in solids are not always harmful and often render materials with many fascinating physical properties. Especially, point defects may either act as color centers enabling electron–hole recombination or exist as effective trap states in a variety of optical materials. While their role as color centers paves the way for developing many activator-free phosphor materials, defect-related trap centers play the most crucial role in activator-based long persistent and mechanoluminescence phosphors. As they both have potential applications in many advanced scientific and medical fields, tailoring defect centers to generate effective traps is a promising research area. Detailed knowledge of controlling defect-related trap centers in materials followed by tuning and optimizing optical properties in a desired range is necessary for developing efficient LPPs and ML materials. In this chapter, we have given a brief description of various point defects, their characterization, and tailoring their related trap states for optimizing their long persistent and mechanoluminescence performance for broad potential applications. This work will facilitate the future development of more efficient trap-controlled long persistent and mechanoluminescence phosphors.