ABSTRACT
This chapter discusses some important terms that are related to luminescence, phosphors and their mechanisms, rare earth-transition spectroscopy, and so on. Phosphors are defined as solid luminescent materials that have the ability to absorb incident light and then to emit light in a longer wavelength range. The phosphor is composed of an inert divalent or trivalent host lattice doped with a rare earth-transition series element. The luminescent materials called phosphors are basically inorganic solid white-colored materials. They are composed of a host lattice and a luminescent center, frequently called an activator. The chapter also discusses the major advantages of phosphors in compact fluorescent lights (CFLs), light-emitting diodes (LEDs), and display devices. Phosphor-converted white LEDs are the most promising and famous sources of white light. The phosphors used in the display have some special characteristics, such as high contrast, better resolution, thermal stability, packing density, and adhesion, which can be fulfilled only by the use of nanosized phosphors.
