摘要
This work presents the synthesis of Y_(2)O_(3):Eu^(3+),χCa^(2+)(χ=0 mol%,1 mol%,3 mol%,5 mol%,7 mol%,9 mol%,11 mol%)nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic,display,and lighting applications.The X-ray diffraction(XRD)patterns of the proposed nanophosphor reveal its structural properties and crystalline nature.The transmission electron microscope(TEM)results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca^(2+).Fourier transform infrared spectroscopy(FTIR)and Raman vibrations also confirm the presence of Y-O vibration and subsequently explain the crystalline nature,structural properties,and purity of the samples.All the synthesized nanophosphors samples emit intense red emission at 613 nm(~5D_(0)→~7 F_(2))under excitation with 235,394 and 466 nm wavelengths of Eu^(3+)ions.The photoluminescence(PL)emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength,respectively.The emission intensity of Y_(2)O_(3):Eu^(3+),χCa^(2+)(5 mol%)is increased 8-fold as compared to Eu:Y_(2)O_(3).Doping with Ca^(2+)ions enhances the emission intensity of Eu:Y_(2)O_(3)nanopho sphors due to an increase in energy transfer in Ca^(2+)→Eu^(3+)through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria matrix.It is also observed that the optical band gap and the lifetime of the~5D_(0)level of Eu^(3+)ions in Y_(2)O_(3):Eu^(3+),xCa^(2+)nanophosphor sample gets changed with a doping conce ntration of Ca^(2+)ions.Nanophosphor also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%,respectively.CIE,CCT,and color purity values(>98%)show an improved red-emitting nanophosphor in the warm region of light,which makes this mate rial superior with a specific potential application for UV-based white LEDs with security ink,display devices,and various other optoelectronics devices.
基金
University Grants Commission(UGC),India for providing research fellowship
DST,New Delhi for fellowship under the Women Scientist Scheme-A with file number SR/WOS-A/CS-52/2018
Institute of Eminence(IOE),Banaras Hindu University(BHU),India for financial support。
