Synthesis characterization and luminescence properties of rare earth and transition metal ions doped oxide phosphors

Abstract

Nanostructured materials are the entities that appear between molecular/isolated newlineatom and extended solids. Recent research on luminescent nano materials provide newlinechallenges to both sensing in biomedical engineering, environmental control, etc. newlineNano phosphors may have a number of potential advantages over traditional micronsized newlinephosphors. Such Nano sized phosphor particles are reported to be somewhat newlinedifferent in their electrical, optical and structural characteristics. Further, the newlinedifferences in electrical and optical characteristics of lt15nm sized particles may cause newlinequantum confinement due to high surface to volume ratio, which results in newlineenhancement of their luminescence efficiency. Therefore, synthesis routes play an newlineimportant role in synthesizing the nanomaterials and evaluating various properties. newlineTraditionally multi component ceramics have been prepared by solid-state newlinemethod, which involve physical mixing of hydroxide, oxide, carbonate, nitrate or newlinesulphate raw materials followed by high temperature treatment, (1500 oC) with newlineseveral calcinations temperature to enable the formation of target material. This newlinemethod results in powders with coarse grained, agglomerated structure with very low newlinesurface. High temperature is required for solid-state material formation, which give newlinerise to poor sintering behaviour, inhomogeneous microstructure, possibly abnormal newlinegrain growth and lack of control of cation stoichiometry, formation of large particles newlinewith low surface area introduces impurity and defects, which are harmful to newlineluminescence. newline newline