Cool green-emissive Y2Si2O7:Tb3+ nanophosphor: auto-combustion synthesis and structural and photoluminescence characteristics with good thermal stability for lighting applications

Abstract

A cheap, versatile, sustainable and energy-efficient gel-combustion method was applied to develop a series of green-emitting down-converted Y₂Si₂O₇:Tb³⁺ (YPS:Tb³⁺) nanophosphors. Employing XRD-based Rietveld refinement approach, the phase purity and crystallographic evaluation of the produced phosphor were conducted, revealing a triclinic crystal with P space group. EDX and TEM analyses were performed on the synthesized samples to determine their elemental composition and morphological properties. Diffuse reflectance spectra yielded 5.61 eV and 5.79 eV optical energy band gaps for the host and the optimized (0.04 mole of Tb³⁺) sample, respectively. UV light has the ability to excite the nanocrystalline phosphor in an efficient manner, leading to significant luminosity qualities attributed to the radiative relaxation of ⁵D₄ → ⁷F_J (J = 6, 5, 4, 3). The bi-exponential decay function was derived by the PL decay curves. With an activation energy of 0.2206 eV, the Y_1.96Si₂O₇:0.04Tb³⁺ phosphor exhibits good thermal quenching capabilities. Improved photometric attributes including CIE coordinates, CCT and color purity confirmed the green glow, indicating a strong competitor for cool-green emission in lighting applications.