Structural and Luminescence Properties of Some Rare Earth Doped Phosphor Nanomaterials

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The word "Luminescence" originates from the Latin word "lumen" which means "light". Luminescence is the process through which a substance emits light after absorbing energy. According to the stroke's law, some of the energy of radiation that strikes a substance may be absorbed and then re-emitted as light with a longer wavelength. This is how luminescence works. The luminescent substance determines the wavelength of the light that is emitted not the incident radiation. Although studies of luminescence phenomena typically focus on the emission of visible light, other wavelengths, including ultra violet or infrared, can also be produced [1]. Luminescence is the phenomenon which was not identified easily, although its different kinds were observed in many instances. Aristotle, who lived in Greece from 384 to 322 BC, noticed that rotting fish gave out light and noted it in his work De Coloribus, state that "Somethings though they are neither in their nature fire nor any species of fire, yet seem to produce light". A Spaniard named Nicolas Monardes wrote about the extraordinarily strong blue color of an aqueous extract of a wood called lignum nephriticum (Mexican kidney wood in 1565. About ninety years 1584, Athanasius Kircher in Germany, Francesco Grimaldi in Italy, Robert Boyle and Isaac Newton in England, and others examined this answer. Everyone observed that it appeared strongly blue by reflection and yellow by transmission when illuminated with white light. The bright blue light was not recognized as luminescence emission by anyone. Later, George Stokes of England made similar determination using prisms and optical filters. He demonstrated how incident light from one spectral region was absorbed by the solution and changed into light that was emitted from a different, longer-wavelength spectral region.