Optical and structural properties of rare earth doped calcium silicates derived from agro food wastes

Abstract

Agriculture sector is expanding rapidly and is generating a significant amount of waste. Residues of crops like corn, rice, sugarcane, wheat are often burnt in open fields despite of the environmental implications. Along with the agriculture waste, huge portion of the total food produced is also being wasted. Without proper disposal mechanism this waste is left to rot by itself. From the perspective of environment and energy needs, the effective way to deal with the problem of waste management is to utilize these wastes to synthesize value-added products. Rice husk ash (RHA) and egg-shells (ES) are the most widely produced agro-food wastes. RHA and ES are found to be promising sources of SiO2 and CaCO3. Thus, RHA and ES are being used as resource materials to synthesize calcium silicate products. Calcium silicates have garnered a lot of interest because of their characteristic features like thermal and chemical stability, and transparency to visible light. Calcium silicates are considered good hosts for synthesizing rare-earth doped phosphors. Phosphors have become integral component of light emitting diodes which has resulted in extensive efforts by various researchers to develop highly efficient phosphor materials. Rare-earth doped phosphors produce emission in a wide range of the visible spectrum. Utilizing agro-food wastes as resource materials for synthesizing calcium silicate phosphor can be an effective approach of managing the widely available waste. The present work is based on the synthesis and characterization of rare-earth (Dy3+, Sm3+, and Eu3+) doped calcium silicates derived agro-food wastes like RHA and ES.