Mimosa pudica mediated praseodymium substituted calcium silicate nanostructures for white LED application

In this paper a simple green route was adopted for the synthesis of orange light emitting CaSiO3:Pr3+ (1-11 mol %) phosphors using Mimosa pudica L. extract as a fuel. The final product was well characterized by powder X-ray diffraction (PXRD), Fourier transform infra-red spectroscopy, diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy. The concentration of plant extract plays an important role in controlling the morphology as well as the formation of superstructures. The obtained superstructures from SEM studies resembled the naturally existing structures like dates, cactus, coconut shell, etc. The energy band gap estimated using DRS was found to be in the range of 5.23-5.47 eV. The emission peaks at 550, 606, 650 and 733 nm were due to the transitions of P-3(0) -> H-3(4, 5), F-3(2, 3). The Commission International de I 'Eclairage and colour correlated temperature coordinates were estimated for all the concentrations of Pr3+ ions and the results indicates that the phosphor may be quite useful in cool light source. The crystalline nature and phase was confirmed by PXRD for the calcined samples at 950 degrees C for 3 h. This was the lowest formation temperature reported in the literature for Pr3+ doped CaSiO3. FTIR results showed the stretching vibrations of Si-O at 720 cm(-1), asymmetric stretching vibrations of Si-O-Si bonds at 560 cm(-1). The present preparation method was simple, eco-friendly, inexpensive and free from unwanted by-products which can be used for large scale production. (C) 2016 Elsevier B.V. All rights reserved.