Morphology control, spectrum modification and extended optical applications of rare earth ion doped phosphors
Rare earth ion (RE3+) doped nano-phosphors with controllable morphologies have a wide range of applications in laser crystals, LEDs, bio-probes, photo-catalysis, three-dimensional displays, sensors, and flash memories. This review summarizes the morphology control strategy, phase transfer theory, spectrum modulation, and extended optical applications of RE3+-doped phosphors. The roles of surfactants in the morphology control in the liquid–solid–solution phase transfer process for RE3+-doped fluorides, oxides and other compounds are discussed. The relevant mechanisms of controlling morphologies are illustrated. The size- and shape-dependent optical properties of RE3+ doped phosphors, including the emission intensities, intensity ratios of adjacent emission bands, decay times and thermal stability, are analyzed. The extended optical applications and main challenges of RE3+-doped phosphors are also discussed.