Revival of stifled luminescence in the Y2Sn2O7:Eu nanophosphor: circumventing the surface side effects by Zr–Eu synergy

Abstract

Although the smaller size of nanophosphors renders processability and flexibility for next-generation devices, concurrent surface prolificity stifles the phosphor efficiency, and in turn, their superiority. To circumvent the surface side effect in the Y₂Sn₂O₇:Eu nanophosphor, the present work articulates a co-substituent (Zr⁴⁺)-assisted revival of stifled luminescence. Steady-state and time-resolved photoluminescence studies revealed that with respect to nanophosphors without a Zr substituent, the Zr-substituted Y₂Sn_2−xZr_xO₇:Eu (x = 0.25, 0.5) pyrochlore nanophosphor exhibited multi-fold augmentation in lifetime and quantum efficiency values, which are key parameters for ascertaining the photoluminescence performance. The experimental and theoretical outcomes indicate that Eu³⁺ prefers to be in close proximity to Zr⁴⁺ ions in the Y₂Sn_2−xZr_xO₇:Eu (x = 0.25, 0.5) pyrochlore lattice to counterbalance the individual substitution consequences and generate appropriate electronic distributions and polar interactions. This proximity preference of Zr–Eu facilitates the occupation of Eu³⁺ in the interior region of nanoparticles and avoids the surface sensitivity. Furthermore, the lifetime values for the Y₂Sn_2−xZr_xO₇:Eu (x = 0.25, 0.5) pyrochlore nanophosphor are 5–6 ms, and the internal quantum efficiency is approximately 80%, which is the highest of any pyrochlore nanosized phosphor reported thus far, to the best of our knowledge. Thus, this work deciphered an innovative pathway for evasion of the surface-quenching effect without compromising homogeneity in the structural ordering and vicinal symmetry of the dopant/substituent across the dimensions of nanophosphors.