Utilization of Agro-Food Waste Materials to Derive β-Ca2SiO4:Eu3+ Phosphors for Near-UV Excited Light Emitting Diodes

Abstract

The sugar cane baggage ash and chicken shells are the abundant by-products of agro-food waste materials. These waste materials have hazardous impacts on the environment and thus it is a prerequisite to utilize these materials for the development of valuable products. The present report is a detailed study to use these materials to fabricate intense red-light emitting Eu-doped Ca2SiO4 phosphors via conventional solid-state method. For this purpose, silica (SiO2) is extracted from sugarcane baggage ash at 600 ℃ via alkali extraction followed by acid precipitation method. The raw eggshells were washed, dried and calcined in the furnace at 900 ℃ in order to get calcium oxide (CaO). The structural, morphological, elemental, optical and luminescent properties were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersed X-ray spectroscopy (EDX), UV-Visible spectroscopy (UVVis), Fourier transformed infrared spectroscopy (FT-IR) and photoluminescence (PL) techniques. The effect of Eu concentration (0.1 to 0.5 mol%) on the structural, optical and luminescent properties of Ca2SiO4 has been studied in details. The agro-food waste derived phosphors exhibited intense emission at 625 nm corresponding to 5D0 → 7F2 transitions of Eu3+ ions under near UV-light excitation at 393 nm. The quenching mechanism and type of energy transfer interactions involved are studied via Blasse and Dexter’s theory. The photometric parameters such as CIE co-ordinates, CCT values, and color purity are calculated from emission spectra. The present agro-food waste derived phosphors are expected to be promising candidates for near UVexcited white light emitting diodes in solid-state lighting and optoelectronic devices.