State-of-the-Art Developments in Luminescent Nanophosphors for Solid-State Technologies

The luminescent nanophosphors are advanced functional materials with excellent optical performance, tunable emission characteristics, high quantum efficiency, and good thermal and chemical stability, suitable for next-generation solid-state technologies. This review summarizes the recent advances in luminescent nanophosphors by highlighting the Principles of photoluminescence, host materials, luminescence mechanisms, enhancement methods, characterization methods, and technological applications of these phosphors. The effects of rare-earth and transition-metal doping, energy transfer phenomena, core–shell structures, quantum confinement, and plasmonic effects on the enhancement of the photoluminescence properties are critically analyzed. Advanced characterization techniques which permit the correlation of structural, optical, compositional, and thermal properties with luminescence behavior are also reviewed. Moreover, the paper emphasizes the growing possibilities of using nanophosphors in phosphor converted white light emitting diodes, optical thermometry, high resolution display techniques, and anti-counterfeiting and forensic devices. Although marked advances have been made, there are still problems of concentration quenching, thermal degradation, scale production, and long-term stability. Future studies that combine defect engineering, computational materials design, and sustainable synthesis will likely help to speed the advancement of the highly efficient nanophosphors necessary for new photonic and optoelectronic technologies.